Class 6 Science

Chapter 4 Rocks And Minerals Different Types Of Rocks

Rocks are so common in nature that we come across them, every time, we visit a hill station in the form of the hard substance that makes up a mountain or while travelling on a train, we find these rocks lying near.

The railway tracks or at a riverside in the form of a rounded pebble or simply in heaps by the side of a road ready to be used in construction.

The earth’s crust is actually made up of various types of rocks that differ from one another in colour, structure, mode of formation, resistance to erosion, etc. The surface rocks are covered by soil or clay in most places.

Rocks are natural substances composed of solid crystals of different minerals that have been fused together to make solid lumps.

These may be classified into three major types- Igneous, sedimentary and metamorphic according to their mode of origin and appearance.

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Chapter 4 Rocks And Minerals Igneous Rock

The word igneous comes from the Latin word ‘ignis’ meaning fire. This is a clue to the fact that the rocks were originally very hot.

It is believed that just after the earth was created, it was very hot and was made up of molten rocks. In the course of time, these molten rock materials cooled down slowly into solid rock.

Thus, the first hard rock formed on or under the earth’s crust is called igneous rock, also known as the primary rock.

Igneous rocks are formed by the cooling and solidification (hardening) of lava on the earth’s crust or magma under the earth’s crust.

Formation & types: Deep inside the earth due to increasing temperature and pressure the rocks remain in a molten state as magma. This magma rises to the surface through cracks in the crust.

While coming out it undergoes changes in temperature and pressure that cause it to cool, solidify and crystalize beneath the surface of the Earth’s crust.

These rocks are known as intrusive igneous rocks. Intrusive igneous rocks are very hard and often coarse-grained in texture.

Examples of these types of rock are granite and gabbro. When the magma comes out of the cracks of the crust or through the crater (vent) of a volcano it is called lava.

This lava cools and solidifies on the earth’s surface quickly to form another kind of igneous rock, known as extrusive igneous rock.

Extrusive igneous rock is fine-grained. Examples of this type include basalt and pumice.

Granite, basalt and pumice are the three commonest types of igneous rocks.

Granite is a light-coloured igneous rock with grains large enough to be visible to the unaided eye. Granite is widely used in most construction activities because of its strength.

Basalt is a fine-grained dark-coloured (usually black) rock of volcanic origin. They are the stones commonly seen near railway tracks.

Pumice stone is actually a volcanic rock which may or may not contain crystals. It is dark-coloured and denser.

It is usually ejected from a volcano. Pumice is formed when there is rapid cooling and depressurization. Holes are usually seen on the pumice stone.

These holes are formed when the dissolved gases of the hot magma escape in the air and the froth at the top of the hot magma quickly cools and solidifies.

Pumice stones are commonly used as abrasive materials in consumer products and aggregate in concrete mixtures.

Chapter 4 Rocks And Minerals Sedimentary Rock

Rocks that are formed through the layerwise deposition and solidification of sediments, especially sediments transported by water (rivers, lakes and oceans), glaciers and wind, over a long time span are called sedimentary rock.

Formation:

Sedimentary rocks are formed by the deposition and subsequent cementation of sediments, within the bodies of water like seas, lakes, etc.

The sediments are actually broken rock fragments derived from the primary igneous rocks.

These rocks were exposed to the action of the agents of erosion like rain, wind, rivers, glaciers etc. and the eroded materials were transported and deposited in layers over a long time, underwater.

When sedimentation continues the older rock layers become buried deeper. Over a long period due to the increase of heat and pressure of the overlying sediments, the underlying

Chapter 4 Rocks And Minerals Metamorphic Rock

Metamorphic rock is a type of rock that is formed when the igneous or sedimentary rocks transform or change physically and/or chemically, due to very high heat and pressure.

The upper layer of the earth is mainly formed of primary (igneous) and secondary (sedimentary) rocks.

The metamorphic rocks are found under the earth’s surface and their sediments get compacted and cemented and turn into sedimentary rocks.

We find petrified remains (fossils) of animals, plants and other microorganisms in the sedimentary rocks as these rocks were formed underwater.

Three common examples of sedimentary rocks are sandstone; limestone and shale.

Sedimentary rocks are deposited in layers as strata and they extensively (73%) cover the earth’s current land surface.

These rocks exist as a thin sheet over the earth’s crust consisting mainly of igneous and metamorphic rocks.

original character and appearance are greatly altered due to metamorphism.

Some common metamorphic rocks are gneiss transformed from granite, marble transformed from limestone, and slate metamorphosed from shale.

Metamorphic rocks are of two types-Foliated (or layered) and non-Foliated metamorphic rocks.

Chapter 4 Rocks And Minerals Minerals And Ore

In the previous chapter, you have learnt about metals, which are solid objects, hard, shiny, good conductors of heat and electricity, can be turned into sheets and their thin pieces can be easily bent.

Iron, copper, aluminium etc. from which nails, wires or utensils can be made are metals. Metals have played a very vital role in the progress of civilisation.

Now the obvious question is how do we get metals? The answer is that our earth is the main source of metals. We extract metals from the earth’s crust.

Earth’s crust is made up of aluminium (8.1%), iron (5%), calcium (3.6%), sodium (2.8%), potassium (2.6%)

What do these indicate? It shows that metals react in the open air to make new compounds.

From the above examples, it can be concluded that metals like iron or copper are found as compounds in nature and not in a pure state.

Likewise aluminium, zinc etc. are similar metals found as compounds.

Gold however does not react when exposed to air or water. It usually remains an element in nature.

Since metals do not occur freely in nature, they are found as compounds mixed with sand and soil, i.e. they occur as minerals.

A mineral is a naturally occurring solid. an inorganic, crystalline substance with a definite chemical composition.

They are formed naturally by geological processes. A mineral can be made of a single chemical element or more usually a compound. Minerals are most commonly associated with rocks.

Rocks may consist of one type of mineral or may be an aggregate of two or more different types of minerals.

When minerals are explored or mined, metals are separated from them. The process of separating metals from the minerals is known as metal extraction.

The type of mineral from which metal can be extracted easily and economically is known as its ore.

Examples: haematite (ferric oxide: Iron + Oxygen) is the mineral ore of iron, bauxite and magnesium (2.1%) among others.

Thus aluminium is the most abundant metal on this planet. It is now important to know, whether, these metals remain as elements or compounds in nature.

If you notice carefully you will observe that an iron object develops a yellowish-red coloured rust, if it remains exposed to air and moisture over a long time.

Again a greenish stain appears on copper utensils when it is left unused for a long time.

(Aluminium + Oxygen) is the mineral ore of aluminium and copper is extracted from its ore copper glance or chalcocite (copper sulphide: Copper + Sulphur).

If a metal has more than one mineral form, then it is not necessary that all of them are ores.

For every mineral deposit, there is a set of conditions, such as the level of concentration of the metal and the size of the deposit that, the deposit may be worked at a profit.

If a mineral deposit is sufficiently rich to be worked at a profit, it will then be called an ore deposit, otherwise not.

So, all ore deposits are mineral deposits, but the reverse is not true.

Chapter 4 Rocks And Minerals Alloys

Metals, after they are extracted from ores, look different from their ores. This is because a chemical change takes place in the process of metal extraction.

The use of steel, brass, bell metal, bronze, etc. in our daily lives is quite common nowadays. These metals are, however, not pure metals like iron, copper etc.

They are combinations of two or more metallic elements.

The homogeneous mixture or combination of different metals or metal and non-metal in a fixed ratio (especially to give strength) are called alloys.

For example, bronze is made up of copper and tin; iron and carbon are mixed to obtain steel; brass is formed when copper and zinc combine.

The two or more component elements that combine to form an alloy are inseparable, i.e. they cannot be readily separated by any physical means.

The major metallic component of the alloy is called the main metal or parent metal or base metal.
Today, more than 90% of metals used are in the form of alloys.

This is because alloys have many advantages, that a single metal does not have.

1.  Alloys are much stronger than a single metal,
2. An alloy has the ability to withstand heavy weight,
3.  It does not readily respond to chemical reactions and
4. Alloys are resistant to corrosion.

Alloys are not always a mixture of two or more metals but may contain one metal combined with other substances, non-metals etc.

An alloy is made by melting two or more elements together, one of which is a metal. When the mixture cools down, a solid substance called alloy is obtained.

Example: Iron mixed with carbon forms steel which is stronger than iron and can support huge weight.

Chromium mixed with iron forms stainless steel which is resistant to corrosion and hardly responds to chemical reactions.

Besides these, gold, duralumin, solder, the metal used to make the electric fuse, etc. are common alloys.

Chapter 4 Rocks And Minerals Fossils

The pictures show the remains of a fish-

1. The shell of a sea snail
2. And the remains of a sea star

We find all these remains engraved in rocks. Once all these were living but with the passage of time their dead remains got petrified or buried in rocks.

These are called fossils. luas After undergoing different changes under the earth over a period of millions of years, the remains of dead animals and plants (living beings of the geologic past) got transformed into rocks.

These rock-like remains of once-living things are called fossils. The preserved impression of an extinct organism’s body parts is also called a fossil.

The trapped body of a dead insect inside the resin of a tree is also called a fossil.

It is really interesting to know how the dead bodies of these animals came inside the rock and got preserved in a hard, petrified form. This process is known as fossilization.

Fossilization:

Millions of years ago the fish, the snail and the sea star were all alive. After the death of these animals, their bodies got buried under water or under the surface of the earth.

The soft fleshy parts of their bodies decayed in the course of time. Soon after the initial decay process, the remains of their bodies got covered with sediments.

The remains, after undergoing a variety of physical and chemical changes over a long span of time, got transformed into rocks.

The impressions or rocky remains of once-living organisms are thus converted into fossils through fossilization or petrification.

Fossils found in sedimentary rocks, act as useful tools for dating the rocks. They also show us the long history of life and the past.

Like animal fossils, plant fossils are commonly seen on coal formed many million years ago. At that time our earth was covered with forests where varieties of plants, ferns, seeds, mosses etc. grew.

The plants grew and eventually died and fell into the shallow waters. New plants grew in their places and later died, got uprooted and fell on the previous layer of decaying plants.

This process of plant growth and their death added layers Raad of decaying plants in the swampy water. Soil, mud and other sediments subsequently covered the decaying plants.

They were gradually pushed underground by the weight. of the overlying layers. The weight of the top layers and heat and pressure caused chemical and physical changes in the plant layers.

As a result, rich coal deposits were formed with impressions of leaves left behind on them.

Chapter 4 Rocks And Minerals Fossil Fuels

The materials such as coal, gas or oil that are burnt to produce heat and power are called fuels.

Coal, gas and oil are obtained from the remnants or dead remains of plants and animals that lived a long time ago.

These dead remains had undergone changes for millions of years and were transformed into fossils.

The trapped solar energy inside the fossils (in the form of chemical energy) produces heat and light energy when these fossilized remains are burnt.

Hence, coal, petroleum (oil) and natural gas are known as fossil fuels.

There are several other types of fuels like wood, paper, hay etc., which do not take millions of years to form. Hence, they are not called fossil fuels.

The pictures show the processes of the formation of petroleum. The pictures show that about 300 million years ago marine animals and plants died and were eventually buried under layers of sediments (silt, sand etc.).

The plants and animals got decomposed partially. Immense heat and pressure acted on the decomposing materials, which resulted in the formation of sedimentary rocks containing petroleum and natural gas.

Finally, we drill through the rocks and sediments to discover petroleum accumulations.

Chapter 4 Rocks And Minerals Uses of Fossil Fuel

Coal is perhaps the most widely used fossil fuel It has various uses. The major uses are outlined below:

1.  As fuel- In the past coal was mainly used to provide heat and raise steam. You must have heard of steam engines or steamships which used coal as a fuel.

Clay ovens used in many households, even today, in rural areas depend on coal for generating fire. Nowadays, the use of coal in both these fields is gradually being replaced by oil or electricity.

2.  Electric power- Coal is still widely used in thermal generators (thermal power plants) to produce electricity. Coal is burnt to generate heat which in turn produces electricity.

3. As coke in the Iron and steel industry-coal is still irreplaceable in the smelting (heating and melting) of iron and steel. Coal can be used to make metallurgical coke for use in blast furnaces.

Coke is produced when coal is heated at a high temperature (about 1100°C) in the absence of oxygen. Coke is essential in the process of extraction of pig iron or hot metal.

Coal tar is also produced from coal as a by-product of coke production. Organic compounds having active hydrogen are separated from tar. The Coke oven gas is used as fuel after it is refined.

Chapter 4 Rocks And Minerals Uses of Petroleum

Oil or petroleum has a wide range of uses as a fuel, as a lubricant, as a raw material for a variety of products etc. The major use of petroleum is in the field of transportation as a fuel.

1. Transport sector :

Petrol (gasoline) and diesel oil are mostly used to drive vehicles like cars, buses, motorcycles, lorries, small boats, military tanks etc.

2. Domestic and commercial cooking gas:

LPG (Liquefied Petroleum Gas) cylinder is used in our kitchen as a common and clean household fuel.

3. Petroleum products:

Petroleum or rock oil is a naturally occurring yellow-to-black liquid which is actually a sticky mixture of various organic compounds, water and soil.

This unprocessed crude oil is refined in a refinery and is made free of water, soil or other impurities to produce various types of fuels. This process is known as the refining of petroleum.

A large number of consumer products like gasoline (petrol), kerosene, asphalt, bitumen or tar etc.

are produced from refined petroleum. Gases such as butane and propane are also produced. LPG cylinders mainly contain liquid propane, butane, propylene, butylene etc.

Chapter 4 Rocks And Minerals Uses Of Natural Gas

Natural gas usually occurs in the uppermost part of an oil trap. The principal constituents of natural gas are a mixture of gaseous hydrocarbons.

Of these methane alone constitutes about 80 to 90 per cent while the other gases include, ethane, propane and butane.

Compressed Natural Gas or CNG is made when purified natural gas is compressed (put under pressure) and stored in a cylinder and used as fuel.

In our country as well as in many other countries CNG is used to run public transport, especially buses, because it Besides its use as fuel, petroleum has become the raw material of a number of chemical industries.

Fertilisers, insecticides and other chemicals for agricultural use; solvents and detergents; plastics, lubricant oil, paint etc.

Are also made from petroleum causing less pollution than other commonly used fuels like diesel or petrol.

In some parts of India, CNG is supplied through underground pipelines to homes and factories to be used as fuel.

CNG is also used in power generation.

 

Chapter 3 Element Compound And Mixture

If we look around us, we can see a wide range of objects. All these objects are made up of a variety of materials.

The tables and chairs are made of wood, the chalk is made of calcium carbonate, and mugs and buckets are made up of plastic.

The almirah is either made of wood or steel, the glasses and plates are made up of stainless steel or plastics, and some of the cooking utensils such as pressure cookers, etc.

Are made up of aluminium, electrical wires are made up of copper or aluminium and so on. A variety of materials are used to build a house.

Concrete and iron [mild steel is required to make bridges. So we can conclude that whatever we see around us is made up of matter.

A matter has some mass; it occupies some space and we can see, touch, smell and taste it. Some examples of matter are air, water, stones, clouds, sand, plants, wood, food etc.

For example, take a piece of stone and put it on the pan of an electronic weighing balance. The balance will show the weight of the piece of stone.

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So the piece of stone has a mass. Now take a glass completely filled with water. Now carefully drop the same piece of stone in it.

You will find that some amount of water comes out of the glass. This happens because the stone is not soluble in water.

It occupies some space within the glass and so it displaces some water from the glass.

Hence we can see that the piece of stone has some mass and it occupies some space. The space occupied by the piece of stone is called its volume.

This type of experiment can be repeated with almost all the matters and it can be shown that each matter has mass and each of them occupies some space.

Chapter 3 Element Compound And Mixture Three States Of Matter

Matter can exist in three different states- solid, liquid and gaseous.

From our everyday experience we know that at ordinary temperatures, plastic is solid and so are iron and aluminium. Hair oil, water, after-shave lotion, petrol, diesel, kerosene, etc.

are all liquid at ordinary temperatures. Air is a mixture of a number of gases. When water is boiled, then steam is formed. Steam is gaseous.

But we should keep in mind that the state of some of the matters can be changed by changing the temperature.

You must have observed that during winter, coconut oil freezes (i.e. solidifies). If we warm it, then it again becomes liquid.

Similarly, water can be transformed into a solid or gaseous state.

Take some water in a plastic container and place it inside the freezer compartment of the refrigerator. Wait for some time.

You will observe that water has transformed into ice. You take out the container containing ice and place it on a table inside the room.  After some time you will find that the ice has melted.

Again take some water in a kettle and heat it by placing it on a gas burner. After some time you will see that steam is coming out from it.

This is an example of a transformation of a liquid state (i.e. water) into a gaseous state (i.e. steam).

If we place a stainless steel plate over the emitting steam, the steam will condense on the steel plate in the form of very small water droplets.

From the above experiments, we can very well understand that one state can be converted into the other by changing the temperature.

Chapter 3 Element Compound And Mixture Classification Of Matter Elements Compounds And Mixture

One may wonder how a particular matter can exist in three different states at different temperatures. For that, we should know how matter is formed.

All matter around us is either pure or impure. Pure matter means that it contains only one kind of particle. Thus it is homogeneous in nature.

For example, sugar is a pure substance since it is made of particles of the same kind.

An impure matter contains two or more pure matters mixed in a certain proportion. Thus it contains more than one type of particle in it.

For example, milk is an impure matter since it contains different types of substances like water, fat, protein etc.

Based on the above matter may be classified as shown below:

particles of extremely small size. If we go on dividing such particles further, a time will come when it will be impossible to recognize each of the very, very tiny particles even by a powerful microscope.

Each of the smaller particles is known as atoms and molecules.

The ancient Hindu philosopher and sage, Kanad first proposed the existence of the atom (para Manu), the smallest part of the matter.

Much later, Avogadro proposed the concept of molecules the smallest part of an element or compound that can exist freely.

A molecule is composed of one or more atoms. A molecule of a particular substance possesses all the properties of that substance.

We have just mentioned two words elements and compounds. Let us know a little Every pure matter can be divided into a bit more about them.

Chapter 3 Element Compound And Mixture Elements

An element can be defined as a pure substance made of one kind of atom which can not be further subdivided by any physical or chemical means.

Examples: Copper, gold, silver, oxygen, mercury, chlorine etc. Thus atom is the smallest particle of an element.

It cannot be further broken into two or more simpler substances. For example, copper is made of only copper (Cu) atoms and silver is made of only silver (Ag) atoms.

There are more than 110 elements known to us to date. Among them, 92 are found in nature (i.e. they are naturally occurring).

The rest have been prepared by the scientists in the laboratory.

The naturally occurring elements are available in the earth’s crust, in the atmosphere and in the seas and oceans.

Oxygen (46.4%) and silicon (27.7%) are the two most abundant elements present in Earth’s crust. Besides, aluminium, iron, calcium, sodium, magnesium etc. are also present.

abundant element present in the earth’s atmosphere followed by oxygen.

Very small amounts of other elements such as hydrogen and ‘inert’ gases are also present in the atmosphere.

All these elements can be classified into three groups:

1. Metals, such as iron, silver, gold, copper, lead, magnesium, aluminium, zinc, mercury, sodium, potassium etc. About 70 of all naturally occurring elements are metals.
2. Non-metals, such as carbon, hydrogen, nitrogen, phosphorous, sulphur, chlorine etc. Non-metals have properties almost opposite to those of metals as is indicated by the name. Only 18 of the naturally occurring elements are non-metals.
3. There are some elements which show properties of both metals and non-metals. They are called metalloids. Examples of metalloids are arsenic, antimony, bismuth etc.

It is important to know the differences between metals and non-metals. While comparing, we should always keep in mind that exceptions are always there.

Comparison Of The Properties Of Metals And Non-Metals

Let us illustrate the above-mentioned properties of metals and non-metals in some detail.

Activity 1: Take a one rupee coin (made of metal) and a piece of charcoal (a form of carbon- a non-metal).

Now drop them from a height onto the concrete floor. When the one rupee coin hits the floor, a sonorous (dong) sound is heard.

This sound is typical for metal. So it is usually referred to as “metallic sound”. But when a piece of charcoal hits the concrete floor, no such sound is heard.

Activity 2: Take a clean stainless steel plate and place it in the sunlight for some time.

The plate shines when sunlight falls upon it. Then if you touch the plate it feels hot. So a metal plate shines in the light and becomes hot quickly.

But this is not the case for any object made up of non-metals. Of course, graphite is an exception.

Activity 3: The surface of a clean, polished metal sheet, say a sheet of aluminium appears to shine in the light, but the surface of charcoal does not. In general, we can conclude that metals have shining surfaces.

Activity 4: Hold one end of a stainless steel spoon over a flame.

Within a very short time, it will become impossible to hold the spoon by hand.

This is because heat is conducted through the metal spoon very quickly from one end to the other.

Although the other end of the spoon is not in direct contact with the flame, heat is conducted pretty quickly from one end to the other through the spoon.

Cooling utensils and water boilers etc are usually made up of copper or aluminium metals since these are the best conductors of heat.

In general, we conclude that metals are good conductors of heat. Non-metals are, in general, not a good conductor of heat.

Activity 5: Take a few pieces of copper wire, one battery, a small flashlight bulb (or a small LED bulb), a pair of iron nails and a piece of charcoal.

First make an assembly as shown in with the bulb, battery and copper wires.

Now connect two ends of the iron nails with the copper wire. The bulb will glow, indicating that an electric current is flowing through the iron nail.

When the copper wire is touched with the piece of charcoal, the bulb does not glow. This proves that electricity cannot flow through the charcoal.

Hence, in general, we can say that metals are good conductors of electricity, but non-metals are not.

The metals are also malleable and ductile. If you go to the workshop of a blacksmith, you will see that iron pieces are being heated and hammered to give them different shapes.

This happens because of the malleability and ductility of iron.

Chapter 3 Element Compound And Mixture Compounds

A compound is a pure substance, consisting of two or more elements, which are combined chemically in a definite proportion.

Let us elaborate on the following experiments.

Activity 6: Take a small rubber cork and fix two iron nails in it. Now place it inside a glass beaker. Pour some water on it.

Add one teaspoonful of lime juice to the water. Stir it thoroughly.

With the help of pieces of copper wire, connect the two iron nails with the two opposite ends of a 9-volt battery.

 

As soon as the iron nails are connected with the two opposite ends of the battery, gas bubbles start evolving from each of the iron nails.

Gas coming out from each of the iron nails can be separately collected and analyzed.

It will be found that hydrogen gas evolves from the iron nail connected with the negative end of the battery and oxygen gas evolves from the iron nail connected with the positive end of the battery.

A word of caution: Never perform this experiment using a connection from the electrical mains of the house or inverter.

You must use a 9-volt battery or 1.5-volt torchlight battery for this purpose.

So you find that when electricity is passed through the acidulated water, it breaks up (or dissociates) to form hydrogen and oxygen.

The phenomena of dissociation of water into hydrogen and oxygen due to the passage of electricity through it is known as the Electrolysis of water.

Properties of Hydrogen 1 It is a colourless, odourless and tasteless gas.

2 It is lighter than air, In fact, it is the lightest element in the universe. Air is approximately 14.4 times heavier than hydrogen.

Oxygen and hydrogen are elements. They are gaseous at ordinary temperature and pressure. But when they “chemically” combine, water is formed in a liquid state.

The properties of water are also different from the properties of oxygen and hydrogen.
Some of the properties of hydrogen, oxygen and water have been summarized below in.

Activity 7: Let us take a gas jar filled with hydrogen. Now a burning taper is introduced in the gas jar.

It will be seen that the flame extinguishes but the gas burns with a “pop” sound with a pale blue inflame.

It proves that hydrogen is not all or supporter of combustion but itself burns (i.e. combustible)

Activity 8: Let us take a gas jar filled with oxygen gas. A glowing splint is slowly introduced into the gas jar.

It is found that the glowing splint rekindles inside the gas jar.

This observation confirms that oxygen gas itself does not burn but it allows other substances to burn, which means it supports the combustion.

From this and it is evident that hydrogen itself burns (i.e. combustible) and is not a supporter of combustion, whereas oxygen does not burn but it supports combustion.

Both these properties are absent in water. In fact, when a fire breaks out accidentally, the first thing we all do is pour water on the fire to extinguish it.

Hence we find that the properties of water are quite different from those of its constituent elements.

Also, if we can analyze water, we will find that each molecule of water is composed of two atoms of hydrogen and one atom of oxygen.

So hydrogen and oxygen combine in a definite proportion to form water. So, we can conclude that water is a compound.

More Examples of Compound

1. When a burning magnesium ribbon is introduced in a gas jar filled with oxygen, it burns very brightly producing blinding white light.

A white powdery substance, called magnesium oxide, is formed due to the burning of magnesium ribbon in oxygen.

Magnesium oxide is a compound formed by a chemical combination of two elements-magnesium and oxygen.

2. When a piece of glowing charcoal (a form of carbon) is introduced in a gas jar filled with oxygen, the charcoal burns more brightly throwing sparks.

Due to this burning, a gaseous compound called carbon dioxide is formed. Its properties are different from that of its constituting elements-carbon and oxygen.

Hence comparing the various properties of carbon dioxide, carbon and oxygen, we can very well understand that in a compound individual properties of its constituent elements are lost.

The characteristic properties of compounds may thus be summarised as:

1. A compound is always homogenous in nature.
2. In a compound, the constituent elements are present in a definite proportion.
3. The properties of a compound are different from those of its constituent elements.
4. The constituent elements of a compound om cannot be separated by simple physical processes.
5.  The formation of a compound is usually accompanied by an evolution of energy in the form of heat and light.

Chapter 3 Element Compound And Mixture Mixture

We have already mentioned that matter can be classified as elements, compounds and mixtures. Let us now understand a little bit about mixtures.

We have mentioned the names of elements such as oxygen, hydrogen, carbon etc. We have mentioned the names of compounds such as carbon dioxide and water.

All these are components of air. In other words, the air is a mixture of nitrogen, oxygen, hydrogen, carbon dioxide, water vapour, etc.

So, scientifically speaking, the air is an impure substance.

1. A mixture is an “impure” substance in the sense that it may contain several elements or compounds or both.
2.  A mixture is prepared by simply mixing some elements or compounds or both in any proportion by weight or volume but without any chemical combination occurring between them.
3. In a mixture, the constituting components remain side by side and each of them retains its individual characteristic properties.
4. The constituents of a mixture can be separated by simple processes.

Compounds also contain more than one element but in a particular compound, the constituting elements chemically combine in a definite proportion.

Also, the individual properties of the constituting elements are lost when they combine to form a compound.

Activity 9: Let us take some iron filings and sulphur powder and mix them together in any proportion. Both iron and sulphur are elements.

Now a magnet is brought closer to the mixture. It will be found that iron filings are attracted towards the poles of the magnet.

So, the characteristic To property of iron (i.e. being attracted towards a magnet) is retained when it is simply mixed with sulphur powder.

So, it is a mixture of iron filings and sulphur powder. Using a magnet, one of the constituents of this mixture can be separated from the other.

Activity 10: Let us now take 7 grams of iron filings and 4 grams of sulphur in a porcelain dish. Heat this mixture until it begins to glow.

A new substance, called iron sulphide (it is actually called ferrous sulphide) is formed. Its appearance is distinctly different from both sulphur and iron.

It is a compound of iron and sulphur. It is not attracted by a magnet. So individual properties of constituting elements of a compound are lost.

Also, unlike a mixture, the constituting elements of a compound cannot be easily separated from one another.

A mixture may be prepared by simply mixing more than one element or compound or both in any proportion.

For example, air is a mixture of mainly nitrogen and oxygen. Other compounds such as carbon dioxide, water, hydrogen, etc.

are present in a very small amount. The relative proportion of nitrogen to oxygen varies with altitude.

At higher altitudes, the oxygen level falls and hence climbers and mountaineers experience respiratory trouble.

The amount of water vapour present in the air also fluctuates from place to place and from season to season.

In places, nearer to seas and oceans, the water content in the air is high. Again during the rainy season the water content in the air increases.

Due to the presence of a higher amount of water in the air, wet clothes require much more time to dry during the rainy season.

So, a mixture may be defined as a material which consists of two or more pure substances (elements or compounds) present in any. proportion.

The pure substances forming a mixture are called the components or constituents of the mixture.

No chemical reaction takes place during the formation of a mixture and all the constituents retain their properties in a mixture.

The mixture is abundant around us. Milk is a mixture of water, fat and proteins. Gunpowder is a mixture of sulphur, charcoal and potassium nitrate.

Crude oil is a mixture of several hydrocarbons. Air, blood, seawater, lemon water, soft drinks, smoke, etc. are other examples of mixtures.

Depending on the state of the mixture and the state of the components of the mixture, several types of mixtures are possible. Such types are listed in Table.

Differences Between Compound And Mixture

Chapter 3 Element Compound And Mixture Types Of Mixtures

Homogeneous and Heterogeneous Mixtures

We have already mentioned that the proportion of different components may or may not vary within a mixture.

Considering the distribution of components, a mixture can be classified as a homogeneous or heterogeneous mixture.

1. Homogeneous mixture:

A homogeneous mixture is one where all the components are uniformly mixed throughout the mixture.

This means that the relative proportion of different components is the same everywhere within the mixture.

For example, let some amount of salt be dissolved in a glass of water. It is stirred very well so that the salt dissolves completely in water.

The salt is now uniformly distributed throughout the water. The water is equally salty throughout. Hence, it is an example of a homogeneous mixture.

“Sharbat” (or a uniform mixture of sugar and water) is also an example of a homogeneous mixture.

2. Heterogeneous mixture:

A heterogeneous mixture is one where the constituting components are not uniformly mixed throughout.

This means the relative proportion of different components varies from place to place within such a mixture.

A mixture of sand and water, a mixture of sand and sugar, muddy water, etc. are examples of heterogeneous mixtures.

Chapter 3 Element Compound And Mixture Solution

Usually, a homogeneous liquid mixture of two or more chemically non-reacting substances is called a solution.

When some amount of sugar is dissolved completely in water, we get a sugar solution.

When some amount of common salt is dissolved completely in water, a salt solution is obtained.

The substance which is dissolved is called the solute, and the substance in which the solute is dissolved is called the solvent.

In the case of sugar solution or salt solution, water is the solvent and sugar or salt is the solute.

In general, we can write, Solution= Solvent+ Solute

Usually, in a solution, the component which is present in a larger proportion is called the solvent and the other component, which is present in a smaller proportion, is called the solute.

The characteristic properties of the solution may be briefly mentioned:

1. A solution is homogeneous and transparent in nature.
2. The solution may be coloured or colourless.
3. The solute particles in a solution easily pass through a filter paper.
4. Solute particles in a solution are so small in size that they cannot be seen with the naked eye or even under a simple microscope.
5. The properties of solute are retained in a solution.
6. The solute particles in a solution do not settle down on keeping.

When solid sugar particles are dissolved in water, they become invisible. Though we cannot see them, we can realize that they are within the solution. Its taste is sweet.

So, the characteristic property of sugar is retained in the

sugar solution. Then why can’t we see them even with a simple microscope? This is because a sugar particle is composed of a huge number of smaller particles.

When dissolved in water, water separates the very, very tiny particles from one another.

Due to this “break up”, the solid sugar particle becomes so small, they spread all over the solution and becomes invisible through our naked eyes or even by simple microscopes.

Chapter 3 Element Compound And Mixture Separation Of Mixture Into Its Components

We have already mentioned that components of a mixture can be separated from one another by simple physical processes.

In our daily lives, we use several techniques to separate the components from a mixture.

For example, milk or curd is churned to separate the butter.

While preparing tea, tea leaves are separated from the liquid by using a strainer.

In villages, farmers use a method called winnowing to separate lighter husk particles from heavier seeds of grains.

If some small pieces of stone are mixed with rice grains, then we remove the pieces of stone by handpicking them.

In our homes, we use a water filter to separate some impurities from water to make it suitable for drinking.

In a flour mill, impurities like husk and stones are removed from wheat by sieving it.

Many of you must have seen that pebbles and stones are being removed from sand by sieving them. Sieves of different sizes holes are used.

the holes should be such that smaller sand grains will pass through the holes of the sieve while the pebbles and stones can’t.

Hence different techniques of separation of constituents of a mixture are used depending upon the characteristic properties of the substances to be separated.

Some methods for separating mixtures are:

1. Winnowing
2. Sieving
3. Hand-picking
4. Decantation
5. Sublimation
6. Filtration
7. Crystallization
8. Magnetic separation
9. Sedimentation, etc.

Below we shall discuss some of the techniques in little more detail.

1. Filtration:

This technique is utilized to separate an insoluble solid from a liquid component.
Principle: Filtration is done by sieving.

The sieve has holes of a particular size. The size of the holes of the sieve should be smaller than the insoluble solid particles which are to be separated from the liquid solution.

The molecules of the liquid are so small that they can pass through the holes of the sieve.

The insoluble solid particles remain on the sieve. Thus the liquid obtained after filtration is pure and devoid of any impurity. Let us illustrate this with an example.

Activity 11: Let us take some amount of muddy water. We want to separate the “mud”, which is an insoluble impurity present in water by filtration.

For this, we need a sieve. A filter paper is used for this purpose. Mud particles are small. But a filter paper has even smaller holes.

The shows the steps involved to fold a filter paper in the form of a cone. The cone-shaped folded filter paper is then placed on a funnel.

The muddy water is then poured into the filter paper. The molecules of water pass through the holes of the filter paper but the mud particles can’t. They remain on the filter paper.

The liquid which is coming out through the filter paper is in general called filtrate while the solid particles that remain on the filter paper are called residue.

 

If the solid is soluble in water, as in the case of a sugar solution or salt solution, the size of the dissolved solid becomes so small that even a filter paper with very small holes cannot separate the sugar or salt from the solution.

In modern days, several water filters are available which can separate very small particles from the water using advanced techniques.

But in ancient times, people used to filter water by passing it through gravels of different sizes and layers of sand.

Application: Filtration tank in public water works.

2. Sedimentation and Decantation:

If the size of the insoluble solid impurity in the liquid solution is big enough, as in the case of sand and water, then sand can be separated from water by sedimentation followed by decantation.

Principle:

The mixture containing solid insoluble impurities is allowed to settle for some time. As a result, the bigger and heavier sand particles gradually settle at the bottom of the container.

This process is called sedimentation. The top layer of the liquid is now free from sand particles and is clear.

This clear top layer of water can then be poured gently into another container without disturbing the bottom layer of sand particles (decantation).

Application: Before cooking, rice and pulses are washed with water and then the water is separated by decantation.

3. Crystallization:

We have just mentioned that salt cannot be separated from salt solution (or sugar cannot be separated from sugar solution) by filtration or sedimentation decantation but since it is a mixture, there must be some simple means to separate salt (or sugar) and water.

Let us go through the undermentioned Activity 12 to learn the technique.

Activity 12: Let us take some amount of salt water in a beaker or any other container. Now boil it for some time.

As a result, some water will vapourize and the solution will become more concentrated. Now allow this concentrated solution to cool down undisturbed.

You will find that some solid salt particles are separated from the mixture. These solid salt particles are called crystals.

The liquid (called mother liquor) can now be slowly decanted and the crystals can be collected.

If we keep the solution for a longer period more water will evaporate and the crystals so formed will be bigger in size.

This process by which crystals of solids are obtained from a solution is called crystallization.

This technique is frequently used by Chemists in the laboratory to separate a particular solid into a pure form.

 

Crystallization is a process of separation of dissolved solid salt from the solution.

During crystallization impurities are retained in the mother liquor and the crystals obtained are of the pure substance.

Application: Purification of salt from seawater, purification of sugar and alums.

4.  Separating a Mixture by using Magnet:

The magnetic separation technique is employed in the case of solid-solid mixtures. We know that iron is attracted towards a magnet. Cobalt and nickel are also attracted by magnets.

They are called magnetic substances.

So, when iron (or any other solid magnetic material) is mixed with some other non-magnetic solid materials like sand, then iron can be easily separated by using a magnet.

When a magnet is brought near to such a mixture, only iron particles are attracted and attached to the poles of the magnet. This way iron is easily separated from the sand.

Application: A strong magnet (such as an electromagnet) is used in the industry to separate scrap iron from the heap of waste materials.

Chapter 3 Element Compound And Mixture Symbol Formula And Valency

By now you have got some preliminary ideas about elements, compounds and mixtures. We already know that elements consist of only one kind of atom.

It cannot be further divided. So the smallest particle of an element is an atom.

A compound is a substance, consisting of two or more elements, which are combined chemically in a definite proportion. The smallest particle of a compound is a molecule.

The molecules of a particular compound can be broken down into its constituting atoms representing the elements.

A molecule of a particular compound has all the characteristic properties of that compound. A molecule is formed when two or more atoms combine chemically in a definite proportion.

The number of each atom in a molecule can be determined by analysis in the laboratory. Below we have listed some compounds and the elements present in each of its molecules.

But the names of the elements and compounds are often quite big. Scientists don’t use such big names when they represent elements and compounds.

They have devised some ways for shorthand representation of elements and compounds.

Chapter 3 Element Compound And Mixture Symbols

Elements are represented by a symbol which is the abbreviated English name (and in some cases the Latin or German name) of an element.

The symbol is given in different ways. For example, some of the elements are represented by the first letter of the name of the element.

But there are only 26 letters in the English alphabet and there are more than 110 elements discovered so far.

So you can clearly understand that using only the first letter of an element will not do. Two or more elements can have the same first letter.

For example, carbon, cobalt, and calcium all begin with the letter “C”. So, only the first letter of the element is not enough to conclusively represent an element.

In the case of barium and beryllium, both have the same first letter (i.e. “B”); the first two letters are used to represent the two elements.

So some elements are represented by the first two letters of the name of the element. Some examples are given.

Chapter 3 Element Compound And Mixture Formula

When two or more atoms combine chemically in a definite proportion, they form molecules. Atoms usually cannot exist in a free state, but molecules can exist in a free state.

But atoms of inert gases [such as helium (He), neon (Ne), argon (Ar) etc. and metals such as gold (Au), platinum (Pt) etc. can exist in a free state.

Molecules of elements or compounds are formed by the combination of the same or different atoms.

It is the smallest unit (or particle) of a substance that can independently exist.

Using the first two letters of an element particular element. For example, thinking of sometimes is not sufficient to represent the first two letters (i.e. “M” and “A”).

In the case of manganese and magnesium-both have the same chromium and chlorine same problem persists.

So in this case, instead of the first two letters, the first and third letters have been used.

Sometimes, to represent some elements, their Latin names have been used. Examples are mentioned below:

Significance of the Symbol:

1. It denotes the name of an element.
2.  A symbol also represents one atom of that element. So “H” means one hydrogen atom, and “2Cl” means two chlorine atoms.
3. It represents the atomic weight of an element. For example, O stands for 16 parts by weight of oxygen element.

A chemical formula represents symbolically the composition of one molecule of a compound or an element.

The formula of an element is written by its symbol with a number placed to its right and a little below it.

The number indicates how many atoms of the element are contained in one molecule of it.

Let us illustrate this with the formula of elemental molecules of hydrogen.

The hydrogen molecule is made up of two hydrogen atoms. So a molecule of hydrogen is represented as “H₂“.

You can see that the symbol of hydrogen (i.e. “H”) is written first and the number of hydrogen atoms in a hydrogen molecule (i.e. “2”) is written as a subscript after the symbol of hydrogen.

In a similar way, the formula of some common compounds may be represented as follows. All these compounds have only one type of element.

The number of atoms present in a molecule is called the atomicity of that molecule.

So atomicity of H₂, N₂, and O₂, is 2; the atomicity of ozone is 3 and that of white phosphorous is 4.

one atom of an element is present in a molecule, then only its symbol is written and is not followed by the subscript ” 1″. So the formula of carbon dioxide is CO₂ (and not C₁O₂).

But not all the molecules contain only one type of atom. Most of the compounds contain two or more different types of atoms.

For, example, a molecule of carbon dioxide contains two different elements-carbon and oxygen. Each molecule of carbon dioxide has one carbon atom and two oxygen atoms.

According to the internationally accepted rule, carbon should be written first followed by oxygen. So it should be represented by the formula C₂O_2.

When only Below we have provided some more examples.

While writing the names of the compound prefixes indicating the number of a particular atom are used before the name of that element.

Mono is used for 1, bi or di is used for 2, tri is used for 3, tetra is used for 4, Penta is used for 5, Hexa is used for 6, and so on. Some examples are given below.

The formula of a compound, therefore, expresses its composition as well as the number of atoms of each of its components.

The formula Na₂CO₃ shows that the elements composing the molecule are sodium, carbon and oxygen and the corresponding number of atoms of the said elements are 2, 1 and 3. Therefore, the atomicity of Na₂CO₃ is 6.

Significance of formula:

1. It states the name of a compound or an element. It also represents one molecule of a compound or an element.
2. A formula expresses the names as well.
3. The formula of an elemental molecule tells the number of atoms present in one molecule of it.
4. A formula expresses the molecular weight of an element or compound.
5. From a formula, it can be known which elements form the compound and in what proportion of their weights they exist.
6. The formula of a gaseous element or compound can give information about its volume and pressure.

Chapter 3 Element Compound And Mixture Valency

Atoms of various elements combine with each other to form the molecules of compounds.
We now know the formula of hydrogen sulphide. It is H₂S.

So in this case one sulphur atom is combined with two hydrogen atoms in a molecule. Similarly, in methane (CH₄), one carbon atom is combined with 4 hydrogen atoms.

In ammonia (NH₃) one nitrogen atom is combined with 3 hydrogen atoms.

The valency of an element means its combining capacity with another element with which it chemically combines to form one or more compounds.

This combining capacity of an element is measured by the number of hydrogen atoms with which one atom of the element combines the number of atoms of the elements present in one molecule of a compound.

The number of hydrogen atoms that combine with one atom of a particular element to form a compound is called the valency of that element in that particular compound.

The valency of the element is determined by assuming the valency of hydrogen to be unity, ie. 1. This is called the valency with respect to hydrogen.

It may so happen that the same element combines with different numbers of hydrogen atoms forming another compound.

So in that case the valency of that element will be different.

We will not elaborate on this at this stage. Below we have listed the valencies of some elements with proper explanation.

You should remember the valency of different elements. This will help you to write the formula of a compound. You will learn more about this in higher classes.

 

Chapter 2 Phenomena Around Us

Changes are acts or processes through which something becomes different. In nature, various changes are taking place continuously.

Even if we do not notice, changes are occurring on a regular basis.

Changes in the weather, drying of clothes, cooking of rice and vegetables, formation of curd or paneer from milk, electric light and fan being switched on or off, burning of wood or kerosene oil, etc. are only a few instances. Some of the changes are taking place around us on their own, while some of the changes are occurring due to our activities.

For example, in our body, hairs and nails grow on their own. As we eat food, they are digested in our stomach. As you grow up, you slowly become taller and gain weight.

All these processes occur “naturally”. You cut a piece of paper with a pair of scissors or you draw a picture in your drawing book. Your mother cooks food in the kitchen.

All these changes occur because we “do” it.

So, you can very well understand that not all the changes are of the same type.

Read And Learn More: WBBSE Notes For Class 6 School Science

Let us systematically study these changes. As a first step, we need to group them. If we find similarities, then we can classify such changes in a particular group.

This will help us to understand the process changes better. Classification of changes into groups can be done in more than one way.

All changes can be categorized into one of the following ways

1. Reversible and Irreversible changes
2. Periodic and Non-periodic changes
3.  Desirable and undesirable changes
4. Natural and Man-made changes
5. Slow and Fast changes
6. Physical and Chemical changes Let us illustrate changes in some detail.

Reversible And Irreversible Changes

Let us take some water in a plastic container. Keep it inside the freezer compartment of a refrigerator. Close the door of the refrigerator and wait for some time.

Now open the door and you will find that all the water has been transformed into ice. Now take out the plastic container containing ice, and keep it on the table in your room.

Again wait for some time. You will find that the ice has melted and has been transformed into water.

Let Us Consider Another Two Examples.

1. Take some amount of wax on a steel spoon with a plastic handle. Now carefully heat it by keeping it over a flame.
2. The solid wax will melt and form hot molten wax. Now keep the spoon away from the flame. The hot wax slowly cools down and the melted wax again solidifies.
3. Take a balloon and blow it carefully so that it does not burst. The shape and size of the balloon change.
4. Now allow the air to escape from the balloon. The deflated balloon regains its original size and shape.

 

The above three examples are such types of changes that are called Reversible Changes. But not all the changes can be reversed.

Let us take a balloon. Blow it hard. It grows bigger and bigger and ultimately it bursts. You know very well that there is no way you can get the balloon back to its original shape and size.

Consider Two More Examples :

1.  Take a candle. It is made of wax. If you light the candle, some wax will melt. As the candle continues to burn, its length goes on decreasing.
2. After some time, almost all the wax will “disappear”. The portion of a candle which has been burnt can never be regained.
3. Take a raw egg. Keep it in water and then boil it very well for some time. The egg is now boiled.
4. Again you know that it is not at all possible to transform the boiled egg into a raw egg by any means.

Hence from the above examples, you can understand that there are some changes which
Changes cannot be reversed by any means. Such changes are called Irreversible Changes.

So you can say that these changes are permanent.

Once it occurs, the substances undergoing it can never go back to their original/initial conditions.

The changes that can be reversed whereby the substances undergoing them can return to their previous states after the changes are complete are termed Reversible Changes.

The changes which cannot be reversed whereby the substances undergoing them can not go back to the previous states after the changes are complete are termed Irreversible Changes.

We have listed some common changes and categorized them as reversible or irreversible changes.

Hence, you can see that all the changes, happening around us can be categorized either as a reversible process or as an irreversible process.

Think about some more examples and try to classify them as reversible/irreversible.

Periodic And Non-Periodic Changes

You must have seen a pendulum clock. It is basically a clock with a pendulum. A pendulum resembles a metal ball (called the bob) tied at the end of a thread.

If you hold the other end of the thread and push the ball slightly in any direction, the ball will swing up to a certain distance.

Then it will stop momentarily and then start swinging in the opposite. direction. Again, after traversing some distance it will momentarily stop and will reverse its direction of motion.

Unless stopped, this pendulum continues to move to and fro for some time.

Thus, after a certain period of time, the pendulum repeats its motion (between leftmost and rightmost extreme positions through mean position), again and again.

 

Every one of us has seen a clock. The hands of the clock rotate continuously. The bigger hand counting minutes comes back to the same position after every hour.

The smaller hand counting hours comes back to the same position after every 12 hours. Another hand, counting seconds, comes back to the same position after every 60 seconds.

We have all seen that day changes into night and night changes into day. The monsoon season or rainy season (or any other season) comes back after every year.

So all the above changes are repeated after a fixed time interval. These changes are called Periodic Changes.

But not all the changes are periodic. For example, during the rainy season sometimes there occurs flood in some places. But floods do not occur periodically.

This means floods do not occur regularly in the same place every year. In the year 2004, a tsunami struck some coastal cities of India like Chennai. But this type of natural disaster never occurs after a fixed interval of time.

The same is true for storms, cyclones or landslides mud-slides. All of these are examples of a type of change called non-periodic changes.

The changes which occur again and again after a fixed interval of time are called periodic changes.

The changes which do not take place after a regular or fixed interval of time are called non-periodic changes.

Below in we have listed some changes and categorized them as either periodic or non-periodic changes with short justification.

 Desirable And Undesirable Changes

Changes occurring around us can also be classified as desirable changes and undesirable changes.

For example, if we cut trees unnecessarily, then it is an undesirable change. This is because this leads to deforestation, which can harm Mother Nature.

On the other hand, when a tree grows, then it is a desirable process. When flowers blossom then that also is a desirable change.

Let Us Study Some More Examples.

1. If we throw away the garbage and waste materials on the streets then it is definitely an undesirable change because this can create health hazards.

But if we throw the garbage and waste materials into the garbage bin or litter bin, then it is a desirable process, because this keeps the locality clean and beautiful.

2. If an automobile emits black smoke while moving, then it is an undesirable change. Black smoke creates air pollution.

3. During some functions or social gatherings if someone plays music very loudly using loudspeakers, then certainly that is an undesirable phenomenon.

This creates noise pollution. Playing music very loudly in a densely populated locality can harm old people and those people suffering from heart ailments.

It also disturbs the students from concentrating on their studies.

4. If cow dung is converted into bio-gas, then it is a desirable change. Biogas can be used as fuel and this fuel is environmentally friendly.

5. A thunderstorm or an earthquake is not at all desirable. These natural calamities bring devastation in the form of loss of lives and properties.

Hence, undesirable changes are those which harm nature or affect mankind adversely. Desirable changes are those which do not harm nature or mankind.

Natural And Man-Made Changes

Changes can also be classified as natural changes and man-made changes. For example, any natural calamity such as thunderstorms, earthquakes, floods, etc. are all natural changes.

We cannot control them. Those phenomena which occur on their own or “naturally” and are not controlled by human beings are called natural changes.

But we should also keep in mind that some of the above-mentioned natural processes can also occur due to severe and prolonged detrimental activities of man.

It is easily understood that activities or processes like agriculture, the industrial revolution, and progress in trade & commerce, all major forms of pollution are man-made phenomena.

Below, in we have listed some phenomena which can occur both naturally and also by the activities of men.

Phenomena which occur due to the activities of men are called man-made phenomena. These phenomena are initiated by men.

Man-made activities and natural activities can be either desirable or undesirable.

Below, we have listed some phenomena and categorized them both as natural man-made and desirable undesirable changes.

In the above table, we have described processes which are natural but can be either desirable or undesirable. The same is true for man-made processes also.

We will now briefly discuss a man-made process which can also harm nature if not properly controlled.

Fertilizers, Pesticides And Insecticides

For the growth of plants, they need food and nutrients. These are absorbed by the plants from the soil.

But in various parts of the world, the amount of different nutrients present naturally in the soil varies.

Some are present in higher amounts while some may be present in smaller amounts.

So depending upon the nature of the soil, we have to apply such “food and nutrients” externally, into the soil for balanced growth of the plants. These are called fertilizers.

With the progress of time as the human population started increasing rapidly, they needed more food.

Cultivation of vast amounts of food grains within a short span of time was not possible naturally.

So scientists developed artificial fertilizers in the laboratory and applied them to the plants for enhancing their growth. That way the production of food grains was increased.

Some commonly used fertilizers are urea, ammonium nitrate, diammonium phosphate, ammonium sulphate, superphosphate (or calcium hydrogen phosphate) etc.

But another thing which has to be kept in mind is that fertilizers alone are not enough to guarantee the enhanced production of food grains.

There are several pests and insects which destroy the food grains.

Earlier farmers used to depend on other animals such as frogs and birds to get rid of such harmful pests and insects.

But a significant part of the food grains was lost due to this dependence.

With the advancement of science and technology, scientists developed some chemicals in the laboratory which are “poison” to those pests and insects.

These “poisons” are called “pesticides” (or pest-killers) and “insecticides” (or insect-killers) which need to be sprayed over the agricultural crops to kill harmful pests.

So it seems that preparing pesticides and insecticides are man-made phenomena and they are desirable. But these pesticides and insecticides have harmful impacts on nature also.

After all, these are poison. These are used to kill living beings. So these must be used carefully and judiciously.

Some common pesticides are BHC (benzene hexachloride), malathion, methyl parathion, heptachlor, etc.

The pesticides are sprayed on the crops. As a result pests and insects staying on those plants die.

Correct and scientific use of these chemicals demands that the pesticides and insecticides must be used in small amounts.

After spraying those chemicals, we are to wait for some days.

These poisons are made in such a way that during this time period, they are destroyed naturally in the presence of sunlight and are converted into harmless or much less harmful chemicals.

Only then do the crops become suitable for consumption.

It is a matter of concern that sometimes sections of farmers spray these poisons in large amounts without knowing the consequences.

Some of them also do not wait till the recommended period of time.

As a result, a substantial part of these poisons is not destroyed naturally and remains with the food grains.

If we eat such contaminated food grains, these pesticides and insecticides directly enter our bodies and remain stored in different human organs such as the liver, kidney, brain, etc. for a long time.

They, therefore, cause damage to such organs and result in diseases like cancer, asthma, mental depression etc.

Besides this, indiscriminate use of pesticides and insecticides can kill other small animals also apart from the pests.

If birds eat those “poisoned” food grains they may die prematurely due to toxicity.

The insecticides may dissolve in water and can ultimately reach the nearby ponds and water bodies.

As a result, the small fish living there may die. If we eat those fishes we indirectly experience the toxic effects of pesticides and insecticides.

Even some man-made fertilizers are also harmful to our bodies when present in large excess food grains.

In the past few decades, nature has been severely harmed by uncontrolled and indiscriminate use of fertilizers and insecticides.

Older people sometimes true that they don’t find small fishes used to be found in the agricultural land during the rainy season in their childhood.

A number of varieties of fish have just disappeared within the last few decades.

Scientists blame the uncontrolled use of pesticides, insecticides and fertilizers for this catastrophic phenomenon.

So we must consciously use man-made chemicals only after assessing the threats they pose to nature and wildlife.

Slow And Fast Processes

We have so far classified different processes as reversible or irreversible, natural or man-made; periodic or non-periodic and desirable or undesirable.

But we have not considered the time it takes for a particular process to occur. If we consider this aspect then we can classify all the changes as either slow or fast processes.

Let Us Illustrate With A Few Examples.

1. If you plant a sapling of the mango plant in your garden, then it will take years for the plant to grow up and get mangoes from it. So it is a slow process.
2.  If you pour some common salt in water and stir it with a spoon, it dissolves fairly quickly in water.
3.  When you light a candle, it takes a long time to burn completely. So we get light from the candle for a long time.
4.  If a bomb is exploded, within seconds everything around it is destroyed. So explosion is a very fast process.
5. It takes time to dry wet clothes.
6. It takes time to boil raw rice or egg.
7. It takes time to digest the food materials we consume.
8. It takes years to construct a multi-storied building or a bridge across a river.
   School Science
9. If someone pours some acid slowly into the water with stirring, the solution immediately becomes hot.
10. The process of making curd from milk is a slow process. During this process, a small amount of curd is added to warm milk. It is stirred well and is then set aside for a few hours at a warm place.
    After that milk is converted into curd. So you can see that it is a slow, irreversible process.

Hence, depending on the time required for a process to occur, we can classify the processes as slow or fast processes.

A process occurring within a short time is termed a fast process, while a process taking a long time to occur is called a slow process.

A chemical reaction can also be classified as a slow reaction or a fast reaction. But in some cases, a slow reaction can be made faster by some means.

This can be illustrated by an example.

Activity 1: Take some clear lime water in a glass. Keep it in the open air for a few days. You will see that clear lime water has become milky.

This occurs because lime water reacts with the carbon dioxide gas present in the air and forms an insoluble, solid substance (known as calcium carbonate).

This solid, insoluble substance remains suspended within the solution. So, lime water turns milky.

As you can see that it takes a few days for the above chemical reaction to occur. Definitely, this reaction is a slow process.

It is slow because the concentration of carbon dioxide in the air is very small.

So it requires time to produce a sufficient amount of that insoluble substance to turn the clear lime water milky.

But if we can increase the concentration of carbon dioxide we can speed up this reaction.

 

Activity 2: Take some clear lime water in a glass. Now with a piece of straw, blow some air into it. Within a few minutes, the lime water turns milky.

This is because the concentration of carbon dioxide is higher in the air we breathe out. So the chemical reaction occurs more quickly.

A chemical reaction can be made faster by other means also.

Activity 3: Let us take the dilute solution of muriatic acid (which is used to clean bathrooms) in two separate glasses.

Now, in one glass drop a piece of marble and in another glass add the same amount (weight) of crushed marble. What will you observe?

In the case of the crushed marble added to the acid solution, a gas will immediately start evolving and the solid particles will dissolve very quickly.

But in the case of a piece of marble, it will take a much longer time to dissolve in the dilute acid solution.

Why did that happen? When a piece of marble is crushed to powder, the total surface area of the marble increases manyfold.

This increased surface area helps the marble to interact quickly with the acid solution.

When we chew the food properly, they are converted into very small pieces.

Since digestion involves a series of complex chemical reactions, hence, within our stomach, they are digested quickly.

So we should chew the food properly. When vegetables are cut into smaller pieces, they can be boiled faster.

When we spray pesticides or fungicides on plants or when we apply body spray or increase in surface area of a solid substance when broken into pieces can be easily understood when you break a piece of chalk.

Each time you break it into pieces, a new surface is generated deodorant spray on our body, the liquid is converted into very fine droplets, possessing a much higher surface area. So they can act faster.

 

When chemicals are dissolved in a solvent, they become very fine particles and then they can react with one another at a much faster rate.

We have categorized some more processes as slow fast processes in Table.

 

Physical And Chemical Changes

Matters can undergo different changes. Let us now consider whether during such changes the matters remain the same or any other new substances are formed.

For example, when clear lime water is exposed to air for a few days, it turns milky. This is because a new substance is formed.

Again think of some water which is frozen to ice. In this case, no new substance has been formed. Only its state has been changed. Liquid happens.

Only the physical properties of a state have been transformed into a solid state. If we warm the ice, we will again get back water (i.e. the liquid state).

When the surface of iron is exposed to moist air for a prolonged period, rust is formed on the surface.

Laboratory analysis will tell you that “rust” is a different substance, different from pure iron. It is formed due to a reaction between iron, aerial oxygen and moisture.

Take a magnet near iron nails. The magnet will attract the nails. But here, no new substances are formed.

When you burn a paper, it is reduced to ashes. Ash is different from paper. It is formed due to a reaction between paper (cellulose) and oxygen at high temperature

When you dissolve some sugar in water, it “disappears” in the solution. But no new substances are formed.

If you can vapourize all the water (or most of it) you can recover the sugar.

So sugar has not been transformed into any new substances.

From this discussion, you can very well understand that in some cases new substances are formed while in other cases no such thing substance (such as physical state, shape, etc.) changes.

So on this basis, we can classify all changes as either physical changes or chemical changes.

The change which involves only a change in the physical properties of a substance and in which no new substances are formed is called Physical Change.

For example, dissolution of sugar in water, freezing of water, boiling of water etc.

The changes which involve the formation of one or more new substances having a completely different set of features or properties compared to the original substances are called Chemical Changes.

For example, rusting of iron, lime water turning milky when exposed to air, burning of paper or kerosene oil etc.

Let us give you a bit more detail about some of the physical and chemical processes.

Examples Of Physical Changes

1.  A piece of iron is magnetized. This is an example of a physical change. No new substances are formed during magnetization. When it is heated or dropped from a height, its magnetic property is lost. We get back the same material. So this physical change can be reversed.
2. Change of state of matter is an example of physical change. For example, when water is frozen to ice or when water is boiled, only the physical

state of the matter is changed. No new substances are formed. When the ice is warmed, we get back to the water.

When hot steam is condensed on a cool metallic surface, we get back to the water.

So we can see that the change of state, which is a physical change, can be reversed by changing the temperature.

When a glass vessel is accidentally dropped, it breaks into pieces. It is a physical change. The glass vessel is broken into several small pieces, but no new substances are formed.

Though it is a physical change, of course, we cannot get back the glass vessel from so many broken pieces. So it is an irreversible physical change.

4. Tearing a sheet of paper into pieces is a physical change.

5. When you take an empty glass and breathe out on it, the moisture present in the air we breathe out is condensed on the glass in the form of very small water droplets.

When we keep some pieces of ice in a glass, the glass becomes cool and the moisture present in the air is condensed on the cool surface of the glass.

 Examples Of Chemical Changes

1. When rice is boiled in water, raw rice is converted into boiled rice. Some chemical changes occur during this boiling whereby new substances are formed. We cannot get back the original material (raw rice) by simple means.
2.  When iron is exposed to moist air for a prolonged period, rust is formed on its surface. Rust is a new substance. If we remove the rust slowly from the iron surface using a sand-paper and collect it, we will see that particles of “rust” are not attracted by a magnet. So properties of rust are different from that of pure iron. [Be careful while rubbing the rusted iron surface so that no pure iron should come out].
3. When a piece of paper is set on fire, it quickly burns and reduces to ashes. A new substance is formed. It is not at all possible to get back the original piece of paper.
4.  Digestion of food inside our stomach involves chemical processes. New, simpler substances are formed from complex food materials.
5. Ripening of mango involves chemical change, and this change cannot be reversed.
6.  Respiration also involves chemical changes.

Activity 4: Prepare a slurry of turmeric powder with water in one container and some amount of beetroot juice in another container.

Now take several strips of filter paper. Dip some of them in turmeric slurry and a few other strips in beetroot juice. Dry the strips.

Now dip those strips in two different solutions-limewater and lemon juice. Following changes in the colour of the strips are observed.

You can see that colour of the strips changed differently in different solutions. Chemical changes are responsible for this colour change.

This is an example of a chemical process accompanied by colour change.

Changes Involve Energy

We know that unless heated, rice is not boiled. If water is not heated it will not boil. To melt ice, it has to be warmed.

Solid naphthalene when heated directly, transforms into a gaseous state through a process called sublimation.

At room temperature also, it sublimes, but at a much slower rate. So, we see that heat energy is associated with all the above-mentioned processes.

It affects the rate of change. We have mentioned already that any change of state (which is a physical process) can occur only if heat is absorbed from a substance or is supplied to it.

Physical processes may or may not involve the absorption or liberation of heat. When dilute sulphuric acid is slowly added to water, the solution becomes hot.

So, heat energy is liberated during the mixing. When urea is dissolved in water, the solution becomes cold. So heat is absorbed during this physical mixing process.

When two gases are mixed together, no noticeable change in temperature is observed. So heat is neither liberated nor absorbed here.

Any change of state can be realized using heat energy. When heat is supplied, water boils. When heat is extracted, the vapour condenses.

This is the reason that on winter mornings, dew drops are formed on the leaves of grass.

At night, the moisture in the air cools down and condenses as droplets of water on the leaves of grass.

The chemical change also involves the absorption or evolution of heat. For example, when quicklime is dissolved in water, bubbles of gases are evolved and the solution becomes hot.

A chemical change is always associated with a change in energy- either in the form of heat energy or any other form of energy.

In some cases, a chemical process is initiated by heat energy. For example, when a piece of paper is held in flames, only then it catches fire and is reduced to ashes.

So this process occurs at a higher temperature. At elevated temperatures, the paper (cellulose) reacts with oxygen in the air to produce carbon dioxide and other substances.

When a firecracker is lit with a flame, it starts emitting light and sound. In fact, changes can be initiated with other forms of energy also.

In the laboratory, when the electric spark is passed through a gaseous mixture of hydrogen and oxygen, water is produced.

Again, when electricity is passed through water, it is dissociated to produce hydrogen. In this process, carbon dioxide and oxygen.

Lightning is also a kind of high-energy electric spark. When it strikes a tree, the tree catches fire. Every year, many people around the world die because of lightning.

If lightning strikes in nearby places, the electrical and electronic goods that are attached to the plug points are damaged. So during a thunderstorm, electrical equipment must be detached from the plug point.

You can explode caps either by pressing the trigger of a toy gun or by hitting it hard with a stone.

In this case, a chemical process is initiated by another form of energy known as mechanical energy.

Plants can prepare their “food” on their green leaves by a process called photosynthesis water combine in the presence of solar energy to form a new substance-glucose.

This chemical process can occur only in the presence of sunlight. That is why a plant dies when kept in the dark for a prolonged time.

So photosynthesis is an example of a chemical process being initiated by light energy.

When food matters are digested inside our stomach, heat is evolved.

This heat maintains the body temperature and provides energy for different processes occurring continuously within our body.

When you bring one finger close to your nose and breathe out deeply, you can feel that the air you are breathing out is warm.

This is because the inside of our body is warm. The warmth of the human body is the result of the metabolism of food.

Metabolism of food causes the release of energy in our cells which keeps our body warm and fit for work.

Some More Examples Of Physical And Chemical Processes

Let us provide you with some more examples of physical and chemical changes.

Physical changes:

1. All of you must have seen tools which are used to dig the soil. In these tools, iron blades are fixed on a wooden handle.

But how is this done? The iron blade of these tools has a ring which is slightly smaller in size than the wooden handle.

As the iron blade is heated, the ring becomes slightly larger and then the handle easily fits into the ring. When the blade cools down, it again contracts and fits tightly on the handle.

This mechanism is also used to fix a metal ring on the wooden wheel of a cart.

1. A gap is left at regular intervals between the joints of railway lines. This is because, in summer, the rail lines become hot and expand in length.This is a physical change. If this gap is not present, the railway lines would bend.
2.  In winter our lips are cracked. This is because, in winter, water is lost more from our soft and exposed body parts such as lips, heels etc.As a result, the lips are cracked. To prevent this we apply cream or lip balm on them.This creates a protective layer on the lips and prevents the loss of water from the lips. Such loss of water is an example of a physical process.
3.  When vinegar is mixed in pickles, it absorbs water from the fruit and vegetable pieces.So those “dry” pieces of fruits and vegetables can be preserved 600 for a long time at room temperature.
4. The melting of glaciers is an example of physical change which occurs naturally

Chemical changes:

When a banana is kept for a few days, black spots appear on its skin. This is due to some chemical changes.

When a piece of apple is cut and kept open in the air for some time, brown patches appear on the exposed surface. This happens due to some chemical reaction.

When leaves of eucalyptus trees fall on the ground, they are decomposed slowly and the chemicals present within these get mixed up with the soil.

Due to the presence of these chemicals in the soil, grasses cannot grow properly around these trees.

When a living animal dies and is kept in the open for some time, it is decomposed. Some microbes convert various body parts of the dead body into other substances.

So it is a chemical process.

In cities, chlorine water or halogen tablets are mixed with water to kill the germs present in them.

1. Marble floors and tiles are often cleaned with “solid acid” (actually it is called oxalic acid). This cleaning process involves a chemical reaction.
2. The weakening of our bones, the colour of our urine and faeces, the yellowing of teeth and cataracts in the eyes are all the results of some chemical processes.
3. From the examples discussed so far about the physical and chemical changes, we can compare them as follows:

We conclude this chapter by classifying some common changes into different types.

You can add some more examples to this list.

Chapter 1 Interdependence Of Organisms And Environment Man And Other Animals Depend on Plants

Our Family and Our Society

Human beings are social organisms, they live in a society and they have specific roles to play as a teacher teaching, a student studying.

the doctor and nurse look after the ailing patients, a shopkeeper sells items, a policeman ensures the maintenance of law and order and protects the common man, municipal workers keep the city clean etc.

The judges and lawyers ensure that everybody gets justice, a civil servant and minister run the government and in this way, the society remains functional.

and it includes the grandparents, father, mother and the children.

The grandparents usually lead a retired life. They should be looked after properly. They guide the family with their wisdom.

The father usually earns money and does the marketing and the mother or any elderly member does the cooking and looks after the children.

The children study, play and make the place enjoyable. Interdependence means two or more people working together on a common activity or towards a common goal.

Examples of interdependent behaviour among family members may include helping one another to prepare the family meals.

Family represents the unit of society,

Read And Learn More: WBBSE Notes For Class 6 School Science

Again, there are circumstances when family members may have to take the help of someone outside of the family for some reason.

Such instances include taking help from a plumber to repair the tap, from a tailor to stitch the clothes, an electrician to repair faults in electric lines or gadgets and so on.

Thus there exists an enduring interdependence between society and family for mutual benefit, functional and emotional support, economic well-being and above all, overall societal prosperity.

Interdependence Between Plants And Animals

A group of mutually adjusted plants and animals inhabit a natural area as a community.

There is a great deal of interdependence or mutual dependence between plants and animals in a community.

No organism can live alone, they need other organisms to survive. The mutual interactions among the organisms are vital for the survival and functioning of the community as a whole.

Plants depend on animals for CO₂ (raw material of photosynthesis), insects & other animals help in the pollination and dispersal of seeds, earthworms and other organisms making the soil fertile for the proper growth of plants.

On the other hand, animals depend on plants for food, medicines, fibres, clothing, other useful products, supply of O₂, and removal of CO₂, plants are homes and shelters for a variety of animals and provide materials for building and furniture etc.

Thus all organisms depend on one another for survival. This is known as interdependence

Dependence Of Animals On Plant

Green plants and similar organisms (autotrophs or primary producers)produce food for all other living organisms on the Earth.

Food provides energy and nutrients for organisms, such as animals (heterotrophs), that cannot trap energy from the sun through photosynthesis.

Some animals, called primary consumers, eat only plants. Others, known as omnivores, eat plants and animals both. Most humans are omnivores.

However, some people choose to eat only food that comes from plants. Plant-based food supplies vital nutrients that our bodies cannot make for themselves.

These nutrients include vitamins, which are chemicals necessary for the proper functioning of the body; sugar and other carbohydrates, which provide energy; amino acids, which are the building blocks of proteins; oils.

Another concentrated energy source; and minerals, such as potassium, magnesium and calcium.

Humans consume a remarkable variety of plants and plant parts. However, agriculture-the cultivation of plants is a relatively recent innovation in human history.

Many historians believe that the farming of plants began about 10,000 years ago in several parts of the world.

The plants we use as food today are very different from their wild ancestors.

Most food plants evolved through selection by many generations of farmers to produce larger fruits, grains and other edible parts and to be easier to plant, harvest and process.

The wide variety of food we eat today originated in many different and geographically separated parts of the world.

Uses Of Plants

Use Of Plants As Food

Root: Many foods come from plant roots. Important root crops include carrots, parsnips, beets, sweet potatoes, radishes and turnips These food help in the procurement of starch.

Stem: Potatoes, the underground modified stems, are specialized for the storage of Animal Kingdom of Starches. The bulb of onion is also an underground modified stem having an apical bud surrounded by multiple layers of fleshy leaves.

Rhizome includes the irregular fleshy stem of ginger, whose nodes are protected by scaly leaves. It has medicinal importance and is also used in cooked food as a flavouring agent.

The Corm of Amorphophallus is also a large club-shaped structure, consumed as a vegetable.

Other stems used as food include sugarcane, which is enriched in sucrose and Asparagus, and also used as a flavouring agent.

Leaf: Leafy food includes spinach, lettuce, brussels sprouts, and cabbage. All of these look like leaves.

However, food that comes from bulbs, such as leeks and garlic, is also made of leaf parts (the enlarged bases of long, slender leaves).

Celery and rhubarb stalks actually are the supporting stems (petioles) of leaves.

These leaves are a rich source of cellulose, which does not have much food value but is used as roughage.

Flower: Flowers are not eaten frequently, but cauliflower, broccoli and artichokes all are made up of flowers or flower buds. Flowers of gourd and other legumes are also consumed as vegetables.

Fruits and seeds, which develop after flowers are pollinated, are important food sources.

Fruits: Familiar fruits include. oranges, lemons, grapefruit, limes, apples, peaches, pears, grapes, melons, cherries, plums, tomatoes, all squashes, blueberries, green beans etc.

Mangoes, bananas, avocados, figs, breadfruit, eggplant, cucumbers, guava, pomegranates, dates, papaya, olives and zucchini are also fruits.

Fruits are useful sources of citric acid and vitamin C that commonly act as antioxidants.

Sometimes the entire inflorescence is consumed as a compound fruit like pineapple and jackfruit.

Seeds: Seeds often contain stored food resources (carbohydrates, oils, proteins) to fuel the growth of the tiny plants that they contain.

Important seeds that we eat are beans, peas, lentils and chickpeas. All of these are members of the bean or legume family.

Food in these seeds is stored in the fleshy leaves (cotyledons) of the plant embryo. Many nuts consist of seeds or parts of seeds. Examples are walnuts, pecans, almonds and peanuts.

Grains: These are considered to be among the first cultivated crops, and are the small, dry fruits of members of the grass family. Grains look and behave very much like individual seeds.

The commonly cultivated food grasses are called cereals, after the Greek goddess Ceres. Major grain crops include barley, millet, oats, rice, rye, sorghum, wheat and corn (maize).

Rice, probably the most important grain, is the primary food source for more than 1.6 billion people.

Use Of Plants As Fibres

Fibres: Fibre crops are plants that have elongated woody cells in stems, leaves, bark and seeds for support and transport.

These form fibres which can be used to make ropes, textiles, paper, upholstery and mattresses.

the 17th century. This fibre (Gossypium species) which is made from hairs that grow on the surface of the seeds, is the most important source of fibre used in textiles.

Cotton fibres: Cotton comes from plants that produce seed pods filled with ball-shaped clumps of cotton fibre. The seeds are separated from the cotton fibre mechanically.

The process continues by spinning threads from the remaining, seedless white fibre.

The threads are then woven to make cloth, which can be dyed. Cotton was grown in Pakistan’s Indus Valley more than 5,000 years ago.

Cotton was grown and used to make clothing in ancient Egypt. Cotton plants were exported to the Southern United States.

Fibre cells in the leaves of sisal (Agave sisalana) are used to make string, rope and rugs (small carpets); a wide variety of fibre sources, but mainly wood pulp, is used to make paper.

Hessian is a thick rough cloth used for making things such as bags and ropes, made from a plant, either hemp or jute.

Cotton fibres are used for making different types of cloth, they are as follows:

Bark cloth: A type of cloth made from the inner bark of various trees, used in Indonesia, Malaysia and the Pacific Islands.

Buckram: A stiff cotton cloth used for covering books.

Calico: A cloth made of cotton with a coloured pattern printed on it, very often these coloured dyes are made from plant-based pigment.

Cambric: A thin white cloth made from cotton or linen.

Canvas: A strong heavy cotton cloth used for making tents, shoes and sails.

Cheesecloth: A thin light cotton cloth suitable for tropical climates.

Crepe: A soft thin cloth with small folds on its surface, made from cotton or silk.

Denim: A thick cotton cloth that is usually blue and is used especially to make jeans, it was originally introduced for industrial workers but later became a trend in fashion.

Flannel: A soft cotton cloth made of soft fibre used for making clothes and sheets.

Gauze: A white cotton cloth that is very thin and has a loose interwoven texture, used in layers for protecting and treating an injury.

Khaki: Tough cotton cloth used in the making of soldiers’ uniforms, it has a typical brown colour.

Muslin: A light thin cotton cloth used for making dresses, curtains and sheets, it is one of the finest cloth made by human beings.

Organdie: A thin stiff cotton cloth that is used as dress material with a lot of starch.

Rayon: A light smooth cloth made from cellulose (from plant cells).

Flax fibre: Linen is made from fibres made from the stem of flax. Flax grows to a height of 4 feet and has leaves that consist of long, tough fibres.

Flax has been used since ancient times to make clothing. The ancient Egyptians used flax to create linen cloth more than 4,000 years ago and it was used in Medieval Europe to make cloth.

Flax is still used to make fabrics for clothing and it is commonly blended with synthetic materials and wool to add strength to fine yarns.

Hemp Fibre: Hemp comes from the Cannabis sativa plant and has been used to make cloth since ancient times.

In the 1980s, producers were able to make fine cloth suitable for clothing from hemp. This development occurred following the discovery of a process using enzymes that removed the fibres’ roughness while still allowing the fibre to retain its durability.

Designers currently use hemp, blended with other textiles, to make fine cloth, in contemporary designs.

Hemp fibre is resistant to stretching, which allows clothes made or woven with hemp fibre to retain their shape and size.

Hemp typically grows in warm climates, such as those found in tropical regions.

Ramie fibre: Ramie is grown in East Asia and is known as China grass. Ramie fibres have been found in fabrics used to wrap mummies in ancient Egypt.

Ramie fibres are fine and produce delicate silk-like threads when spun, although the fibres can become brittle when a dry process is used to spin them.

Cloth made from Ramie is resistant to stain and has a slight sheen that reflects light. Ramie fabrics are also used in the manufacture of garments because the cloth does not readily shrink.

Plant materials used as building materials

Resins: Resins obtained from plants like pine, sal etc. are used in paints.

There are many other building materials obtained from plants, such as timbers of sal are used in making window frames and furniture. Softwoods are used for insulation purposes.

Plant excretory products may include pitches for waterproofing or making organic solvents for dissolving paints. Fibres are used as thatching material.

Rattans: Rattans (climbing palms) are used for all kinds of purposes, from building shelters to making cane furniture, baskets, mats and fish traps.

Coirs: Coirs are used for making door mats and also for making the lining of the floor.

Use Of Plant Excretory Material

The plant excretory materials are used for different purposes as described below:

1. organic acids like citric acid is obtained from fruits of lemon tartaric acid is obtained from fruits of tamarind.

2. The latex of rubber plants obtained from the bark is used in the making of rubber

3. The resin from Pinus wood is used for producing turpentine, which is used in the making of organic solvent, or as a polishing agent.

4. Essential oil from the flowers of the lavender plant is used in the making of perfume, and lemongrass oil from the leaf is used as a pesticide.

5. Tannin obtained from the leaves and twigs of different plants like tea, and Emblica are used in the making of printing ink or processing of leather.

6. Alkaloids obtained from different plant resources have medicinal importance; some of them are as follows:

1. Caffeine from coffee seeds is a stimulating agent.

2. Quinine from Cinchona bark is a malarial drug.

3. Amarogentin from chirata leaves is used against Salazar.

4. Atropine from the flowers of Atropa is used to dilate pupils.

5. Reserpine from the stem and twigs of Rauwolfia is used to treat high blood pressure

Plants Are The Dwelling Place For Animals

Birds like sparrows, crows, and common mynah directly use the plants as their dwelling places.

They use plant parts like fragments of stems, twigs, and leaves to prepare beautiful nests.

Other animals like squirrels and monkeys live in the trees. Bats hang from the branches of trees. Insects also live in the trees and get their food from them.

Ants and other stinging insects often take shelter on big trees, particularly fruit trees like mango and litchi.

These insects act as an army and protect the plants from enemies whenever necessary.

In some American acacias, a certain part of the leaf becomes hollow to be used as an abode for the insects and even some food materials are kept ready for them.

The insects, in return, render defence service in times of necessity.

Plants As A Source Of Oxygen

Plants have chlorophyll, with which they carry photosynthesis. The process of photosynthesis has two phases, the light-dependent phase and the light-independent phase.

The light phase produces energy-rich compounds and also photolysis of water which generates oxygen.

The dark phase or light-independent phase is involved in the production of sugar by fixing carbon dioxide.

Thus plants provide food and oxygen to other members of the biotic community and absorb harmful carbon dioxide from the atmosphere.

Hence the environment is purified due to the maintenance of O2 & CO2 and global warming is reduced by the prevention of the abundance of CO2 in the earth’s atmosphere.

 Dependence Of Plants On Animals

Pollination

The process of transfer of pollen grains from the anther to the stigma is called pollination.

When it occurs within the same flower, it is called self-pollination but when it occurs between two S different flowers, it is called cross-pollination.

Pollination leads to fertilization, the formation of plant embryos and the subsequent creation of new plants.

Thus the process of pollination is absolutely essential for the existence of the plant kingdom.

The process of cross-pollination is helped by different agents like air, water, animal, etc.

Animals Helping In Pollination

The animals that help in cross-pollination include insects, snails, birds, bats and other mammals like cattle.

1. Insect-pollinated flower:

These flowers have bright colours, they have nectaries and the petals are suited enough to allow the insects to settle down.

In the case of ant-pollinated flowers, the inflorescence is completely closed with an apical pore, through which only the ants can enter, e.g. Calotropis, Salvia, and Sunflower.

2. Snail pollinated flower:

These flowers are semi-aquatic and are protected by a fleshy bract, e.g. arum

3. Bird-pollinated flower:

The flowers are large, and bright in colour, e.g. Bignonia

4. Bat-pollinated flower:

These flowers are large in size, and nocturnal, e.g. Kadam.

5. Cattle pollinated flower:

These flowers are large and are not destroyed even after being trampled by cattle, e.g. Rafflesia.

Fruit And Seed Dispersal

Seed and fruit (which contains the seed inside) dispersal is the movement, spread or transport of seeds or fruits away from the parent plant.

This method has several benefits for different plant species. First, seed survival is higher away from the parent plant.

This higher survival is due to the prevention of actions of seedling predators or pathogens which often target the high concentration of seeds beneath adult trees.

Secondly, competition with adult plants may also be lower when seeds are transported away from their parent plants.

This allows plants to reach specific habitats that are favourable for survival.

Thus dispersal of seeds or fruits is very important for the survival of plant species by spreading out in a wide area and avoiding competition with one another for the same resources.

Since plants are mostly immobile, thus they rely upon several abiotic agents (like wind, water etc.) and biotic agents (birds and animals including human beings) for the dispersal of seeds and fruits. The animals help in the dispersal of fruit and seed in the following way:

1. Berry and other fleshy fruits are consumed by birds. After that, the fruit rot within the alimentary canal and the seed come out with the egested matter and germinate in a different place.

2. Sometimes seeds or fruits have spiny projections, which get adhered to the hoofs of cattle and get dispersed, for example., Xanthium.

3. Seeds of chorkanta get adhered to the fur of animals or in the clothes of human beings and are dispersed through a wide area.

Nature Of The Relationship Of One Living Organism With Another

Symbiosis

It is a unique long-term association between two organisms of the same or different species where they two remain in close association and are mutually benefitted by each other.

Each of the participatory organisms is called a symbiont. There are different examples:

1. Cattle egrets and cattle:

These egrets are small birds (Heron) that remain along with cattle. When the cattle (eg. cows) walk, insects fly out of the grass.

The egrets feed on the insects sitting on the cattle’s bodies and thereby protect them.

2. Clownfish and sea anemones:

The clown fish keeps away the enemy of the sea anemone ie, the butterfly fish and in return, they feed on the remnants of food left over by the sea anemone.

Sometimes the enemies are devoured by the sea anemone.

3. Ants and aphids: The aphid is a sap-sucking insect. The aphids feed on plant

sap producing a sugary compound called the honeydew as excreta which is consumed by the ants.

The aphids remain well protected in the ants’ nest and the ants also carry them from one host plant to another as and when necessary.

4. Mynah and Rhinoceros:

Rhinoceros have very thick skin commonly inhabited by mites. The Mynah or other egrets feed on these mites and thereby provide relief to the Rhinoceros.

5. Hermit crab and sea anemone:

Since they have a soft abdomens, hermit crabs live inside the empty shell of marine animals to protect their vulnerable abdomen. The hermit crab carries the sea anemone on its shell.

The stinging tentacles of the sea anemone protect the crab while the sea anemone can move freely on top of the hermit crab and in return, has a share of food left behind by the hermit crab.

6. Azolla and bacteria:

Azolla is a kind of floating plant. A kind of bacteria called cyanobacteria (Anabaena azollae) takes shelter on its leaves.

This bacteria in turn fixes atmospheric nitrogen to help Azolla. Nitrogen is an essential ingredient of fertilizer. For this reason, Azolla is cultivated in the cropland.

2. Predation

The phenomenon by which one animal feeds on another animal is called predation.

This habit has created a food chain and the animal that is fed upon is called prey, while the animal which is feeding on the prey is called predator.

Some of the predators and prey are given below Predation helps to maintain biodiversity and provides energy to prolong life and promote the reproduction of the predator to the detriment of the prey.

It thus has a controlling effect on the prey population in a community.

3. Parasitism

The relationship in which one organism lives on another living organism derives its nourishment from that organism and thereby gets benefits while the other organism is harmed is called parasitism.

Parasites influence the food web because they function as both predators and prey. Parasites that feed on hosts engage in a special type of predation.

Alternatively, parasites can also serve as important sources of prey.

For example, predators on islands in the Gulf of California (like lizards, scorpions and spiders) are more abundant on islands with seabird colonies because they feed on the bird ectoparasites.

Predators also inadvertently consume parasites during the consumption of infected hosts.

Parasites can be classified in different ways:

1. On the basis of the host:

Plant parasites: Dodder, fungi.

2. Human parasite: TB bacteria, Pig tapeworm.

3. Animal parasite: Dog tapeworm.

On the basis of the part affected:

Stem parasite: Dodder or Swarnalata.

Root parasite: Viscum.

Leaf parasite: Rust fungus or Puccinia growing on wheat plants.

On The Basis Of The Location:

Ectoparasite:

The parasite that remains outside the host’s body is usually on the external surface, e.g. Lice growing on the scalp.

Endoparasite:

The parasite that grows inside the host’s body, very often they are anaerobic in nature, e.g. Pork tapeworm.

On the basis of nature, parasites may be classified as:

Obligatory parasite:

The parasites which are always parasitic and never survive as saprophyte is called obligatory parasites, e.g. Puccinia graminis causing black stem rust of wheat.

Facultative parasite:

These parasites may survive both as saprophytes and parasites in nature, e.g. Aspergillus.

Some of the major parasites:

 Dependence Of Man On Animals

The earth, its ecosystem and its creatures are all deeply connected. Thus, the existence of many species depends on the survival of others.

Human beings are no exception. There are many animals we rely on for our benefit and well-being.

In fact, many animals actually help people just by performing their natural roles in their environment.

Human beings depend on animals with respect to food, clothing, medicines, reduction of pollution and also as a mode of transport.

1. Animals as food:

The animals are the source of different types of food like meat, fish, eggs, milk, honey etc.

Meat is obtained from different animals like goat, cattle, pork and also chicken from poultry birds.

Eggs from poultry birds are useful sources of fat, protein, sulphur, and calcium.

Honey obtained from the honey bee is a useful source of sugar, minerals and vitamins.

2. Animals used for preparing clothes:

Silk thread produced by silkworms is a protein thread used in the making of quality dress material.

The quality of silk varies with the type of silkworm and the plants on which they feed.

Wool obtained from sheep and goats (Angora goats, Kashmiri goats etc.) is another important variety of thread used for making warm clothes.

3. Medicines from animals:

Animal lovers are a very good source of vitamins. The liver of cod and halibut fish are a potential source of vitamins A and D.

Vitamin D is good for bone formation while vitamin A is a potential source of retinol, which helps in the synthesis of rod cells in the retina that are responsible for low-light vision.

4. Animals helping in the reduction of pollution:

Some animals help in the reduction of pollutants. Crows are ideal scavengers feeding on leftover food and organic matter, animal waste and carcasses.

Vultures also feed on animal carcasses and reduce pollution. Pigs feed on animal waste and other organic waste and thus clean the environment.

Some animals like guinea pigs feed on their own excreta, the phenomenon is called coprophagy and thereby they absorb the essential nutrients which they cannot digest at first time.

5. Animals used as transport:

Animals have been used as a mechanism of transport, like bullock carts, horse carriages etc.

In the present day, with the increasing speed of life, these carriages are mostly used in rural areas as means of transport and less used in urban areas.

6. Animals used in agriculture:

Cattle (cow, buffalo or lamb) were previously used in ploughing agricultural land but presently with the increasing use of mechanized agricultural equipment, the use of animals in agriculture has been mostly discontinued.

Microbes Useful To Human

Microbes include microscopic organisms like bacteria, fungi, algae, protozoa etc. which are not visible to the naked eye.

Many of these organisms are useful to humans and are used in the preparation of curd, bread and medicines.

1. Preparation of curd:

Curds are formed from milk by the lactic acid bacteria, Lactobacillus lactis which helps in the fermentation of lactose sugar to lactic acid.

The formation of lactic acid prevents the growth of pathogenic bacteria in the curd.

2. Production of bread:

The dough made of wheat or flour is fermented by a unicellular fungus called yeast to produce bread. Yeast breaks down the sugar present in the wheat or flour.

Carbon dioxide and alcohol are also produced in the process.

Mild heating causes the carbon dioxide to be liberated thereby causing the porous texture of the bread. This way bread becomes soft and spongy.

3. Production of Medicines:

Microbes are a useful source of medicines like antibiotics.

The green mould Penicillium notatum produced the first antibiotic, penicillin as was discovered by Sir Alexander Flamming.

Streptomyces is a bacteria-like organism belonging to the actinomycetes group, which produces antibiotics like streptomycin and erythromycin which are used against pathogenic organisms.

Chapter 3 Element Compound And Mixture Review Questions Environment Review Questions MCQs

Question 1. Which is not an element?

1. Copper
2. Ammonia
3. Gold
4. Carbon

Answer: 2. Ammonia

Question 2. The symbol of sodium was chosen from its Latin name

1. Natrum
2. Hydrargyrum
3. Laplacian
4. Kalium

Answer: 1. Natrum

Read And Learn More: WBBSE Solutions For Class 6 School Science

Question 3. The Latin name of silver is

1. Plumbum
2. Argentum
3. Stannum
4. Ferrum

Answer: 2. Argentum

Question 4. The German name Wolfram stands for

1. Tungsten
2. Tin
3. Copper
4. Iron

Answer: 1. Tungsten

WBBSE Class 6 Science Question Answer

Question 5. Which statement is correct in the case of a mixture of water and sugar?

1. They can be separated out through filtration
2. They can be separated by winnowing
3. Water is a solvent and sugar is solute
4. Water is a solute and sugar is solvent

Answer: 3. Water is a solvent and sugar is solute

Question 6. Which of the following is non-metal but a good conductor of heat?

1. Copper
2. Mercury
3. Graphite
4. Boron

Answer: 3. Graphite

Question 7. Atomicity of Ca(OH), is

1. 5
2. 3
3. 4
4. 6

Answer: 1. 5

Question 8. The elements which are present in a molecule of sugar are

1. Na, O, H
2. 5
3. C, N, O
4. C, H

Answer: 2. 5

Question 9. One molecule of hydrogen sulphide contains

1. One hydrogen atom and one sulphur atom
2. One hydrogen atom and two sulphur atoms
3. Two hydrogen atoms and one sulphur atom
4. None of these

Answer: 3. Two hydrogen atoms and one sulphur atom

Question 10. An example of a metal which is liquid at room temperature is

1. Mercury
2. Aluminium
3. Bromine
4. Iodine

Answer: 1. Mercury

Question 11. The symbol of manganese is

1. Mg
2. Ma
3. Mn
4. Mo

Answer: 3. Mn

WBBSE Class 6 Science Question Answer

Question 12. Which one of the following mixtures is a solution?

1. Chalk powder in water
2. Oil in water
3. Common salt in an aqueous medium
4. Soil

Answer: 3. Common salt in an aqueous medium

Question 13. Identify the wrong statement.

1. The number of atoms present in a molecule is called the atomicity of the molecule
2. Hydrogen supports combustion
3. Oxygen is non-combustible but supports combustion
4. The valency of nitrogen in NH₃ is 3

Answer: 2. Hydrogen supports combustion

Question 14. Ca is the symbol of

1. Carbon
2. Calcium
3. Cadmium
4. Cobalt

Answer: 3. Cadmium

Question 15. The process used to separate a mixture of sand

1. Filtration
2. Crystallization
3. Magnetic separation
4. None of these

Answer: 1. Filtration

Question 16. Which one of the following is not an element?

1. Copper
2. Graphite
3. Phosphine
4. Uranium

Answer:2. Graphite

Question 17. Which one of the following supports combustion?

1. Hydrogen
2. Oxygen
3. Carbon dioxide
4. Nitrogen

Answer: 2. Oxygen

Question 18. Hydrogen and oxygen combine to form

1. Water
2. Methane
3. Salt
4. Alcohol

Answer: 1. Water

WBBSE Class 6 Science Question Answer

Question 19. The substance which is attracted by a magnet is

1. Copper
2. Sand
3. Iron
4. Silica

Answer: 3. Iron

Question 20. Which of the following is not a compound?

1. Water
2. Ammonia
3. Diamond
4. Phosphine
5. None of these

Answer: 3. Diamond

Question 21. The symbol of potassium is

1. P
2. K
3. Po
4. None of these

Answer: 2. K

Question 22. 5N₂ means

1. 5 atoms of nitrogen
2. 5 molecules of nitrogen
3. 10 atoms of nitrogen
4. 10 molecules of nitrogen

Answer: 2. 5 molecules of nitrogen

Question 23. Arsenic is a

1. Metal
2. Non-metal
3. Metalloid
4. Mixture

Answer: 3. Metalloid

Question 24. When electricity is passed through the water, the two gases obtained are

1. Carbon and oxygen
2. Oxygen and hydrogen
3. Hydrogen and nitrogen
4. Carbon and hydrogen

Answer: 2. Oxygen and hydrogen

Question 25. Carbon is a

1. Metal
2. Non-Metal
3. Metalloid
4. Compound

Answer: 2. Non-Metal

WBBSE Class 6 Science Question Answer

Question 26. The lightest element is and water is

1. Hydrogen
2. Helium
3. Lithium
4. Aluminium

Answer: 1. Hydrogen

Question 27. The symbol of silver is

1. Si
2. Ag
3. Au
4. S

Answer: 2. Ag

Question 28. Which one is not attracted by a magnet?

1. Cobalt
2. Copper
3. Nickel
4. Iron

Answer: 2. Copper

Question 29. The formula of hydrogen sulphide is

1. HS
2. H₂S
3. HS₂
4. H₂S₂

Answer: 2. H₂S

Question 30. A liquid non-metal at room temperature is

1. Mercury
2. Sodium
3. Bromine
4. Galium

Answer: 3. Bromine

Question 31. CCI₄ is

1. Carbon trichloride
2. Carbon tetrachloride
3. Carbon pentachloride
4. Carbon hexachloride

Answer: 2. Carbon tetrachloride

Question 32. A polyatomic element is

1. S₈
2. H₂
3. C
4. Does not exist

Answer: 1. Sg

Question 33. An example of an elemental molecule among the following is

1. NH₃
2. CaO
3. H₂SO₄
4. CI₂

Answer: 4. CI₂

Class 6 WBBSE Science Question Answer

Question 34. The smallest particle of an element which may or may not have independent existence is called

1. An atom
2. Molecule
3. A compound
4. An ion

Answer: 1. An atom

Question 35. Which among the following is a pure substance?

1. Dilute sulphuric acid
2. Aqueous NaCl
3. Vinegar
4. Molten NaCl

Answer: 4. Molten NaCl

Chapter 3 Element Compound And Mixture Fill In The Blanks

Question 1. Antimony is a __________
Answer: Metalloid

Question 2. __________ metal is the best conductor of electricity.
Answer: Silver

Question 3. The symbol of beryllium is __________
Answer: Be

Question 4. A mixture of iron fillings and table salt can be separated by __________
Answer: Magnet

Question 5. The symbol of sodium is __________
Answer: Na

Class 6 WBBSE Science Question Answer

Question 6. __________ is a metal which is liquid at room temperature.
Answer: Mercury

Question 7. The formula of ammonia is __________
Answer: NH₃,

Question 8. When magnesium filament is burnt in oxygen, __________ coloured substance is formed.
Answer: White

Question 9. The Latin name of silver is __________
Answer: Argentum

Question 10. In a solution, __________ amount.
Answer: Solvent

Question 11. The atomicity of Ca(OCI)CI is __________
Answer: 4

Question 12. Diamond is a non-metal and it is __________ conductor of heat.
Answer: Good

Question 13. The liquid obtained after filtration is called __________
Answer: Filtrate

Question 14. In the case of a sugar solution (sharbat), the solvent is __________
Answer: Water

Question 15. Chlorine (element) is represented by __________
Answer: CI

Question 16. __________ is represented as PH3
Answer: Phosphine

Question 17. The formula of carbon tetrachloride is __________
Answer: CCI₄

Question 18. The atomicity of chlorine is 2. The formula of chlorine (molecule) is __________
Answer: CCI₂

Class 6 WBBSE Science Question Answer

Question 19. Formula of __________ SF₄ is
Answer: Sulphur tetrafluoride

Question 20. The formula is __________ CH₄
Answer: Methane

Question 21. Solution = __________ + __________
Answer: Solvent, Solute

Question 22. The Latin name of gold is __________
Answer: Aurum

Chapter 3 Element, Compound And Mixture Identify as True or False

Question 1. Iron is a compound.
Answer: False

Question 2. Metal is a good conductor of heat and electricity.
Answer: True

Question 3. One molecule of chlorine contains two atoms of chlorine.
Answer: True

Question 4. Carbon dioxide is a compound.
Answer: True

Question 5. Air is a compound.
Answer: False

Question 6. A solution is a mixture.
Answer: True

Question 7. The valency of oxygen in water is 2.
Answer: True

Question 8. The atomicity of methane is 5.
Answer: True

Question 9. The atomicity of nitrogen dioxide is 2.
Answer: False

Question 10. In a solution, a solute is present in a smaller amount compared to the solvent.
Answer: True

Question 11. Diamond is a non-metal.
Answer: True

Question 12. A valency is always a whole number.
Answer: True

Question 13. The valency of nitrogen in ammonia is 3.
Answer: True

Chapter 3 Element, Compound And Mixture Match the Columns

Answer: A-2,B-6,C-4,D-5

Answer: A-3,B-6,C-1,D-6

Answer: A-3,B-4,C-1,D-2

Answer: A-3,B-4,C-2,D-1

Answer: 1-D-1,2-B-4,3-C-3,4-A-2

Chapter 3 Element Compound And Mixture Answer In Words Or A Sentence

Question 1. One molecule of phosphorous trichloride has only one phosphorous atom. What is the formula of phosphorous trichloride?
Answer: The formula of phosphorus trichloride is PCI₃.

Question 2. Write the symbols of phosphorous and potassium.
Answer: The symbol of phosphorous is P; the symbol of potassium is K.

Question 3. Name two elements for each of which both the symbol and the formula are the same. MonatomicAnswer: molecules like Na (Sodium), and K (Potassium) are such elements.

Class 6 WBBSE Science Question Answer

Question 4. What are the elements present in one molecule of carbon dioxide? Mention their number also.
Answer: Each molecule of carbon dioxide (CO₂) contains one carbon atom and two oxygen atoms.

Question 5. Write the name of the compound: PCI₅.
Answer: Phosphorous pentachloride.

Question 6. How can we obtain pure copper sulphate from the impure sample?
Answer: Using filtration and crystallization techniques.

Question 7. Name the process of separation of sand and camphor from their mixture.
Answer: Sublimation is used to separate them.

Question 8. Write the formula of sulphur hexafluoride.
Answer: SF₆

Question 9. Name the elements present in a molecule of sugar.
Answer: Each molecule of sugar contains carbon, hydrogen and oxygen.

Question 10. What is the valency of carbon in methane?
Answer: The valency of carbon in methane is 4.

Question 11. What is the symbol of argon?
Answer: The symbol of argon is Ar.

Question 12. What is the formula of oxygen gas?
Answer: The formula of oxygen gas is O₂.

Question 13. Name a zero-valent element.
Answer: Inert gas Argon (Ar) is a zero-valent element.

Question 14. Which elements are present in water?
Answer: Hydrogen and oxygen are present in water (H₂O).

Question 15. Write the name of a non-metal.
Answer: Nitrogen is a non-metal

Question 16. Sugar and salt are dissolved together in the water. Identify the solvent and solute.
Answer: Here water is the solvent; sugar and salt are the solutes.

Question 17. Give an example of a mixture.
Answer: Air is an example of a mixture.

Question 18. Write the formula of common salt.
Answer: The formula of common salt is N_aCI.

Class 6 Science Question Answer WBBSE

Question 19. Identify heterogeneous mixture from the following: Air, liquor Ammonia, muddy water, and an Aqueous solution of copper sulphate.
Answer: Muddy water.

Question 20. Write the formula of the following: hydrogen sulphide and phosphine.
Answer: The formula of hydrogen sulphide and phosphine are HS and PH, respectively.

Question 21. What is the symbol of iodine?
Answer: The symbol of iodine (element) is I.

Question 22. Which one is the lightest metal?
Answer: Lithium is the lightest metal.

Question 23. Name two elements which possess both the characteristic properties of metal and non-metal.
Answer: Arsenic and bismuth are two elements which possess both the characteristic properties of metal and non-metal.

Question 24. What is the atomicity of H2SO4?
Answer: The atomicity of H₂SO₄ is 7.

Question 25. Identify the non-metal(s) from the following: potassium, helium, chromium, and iodine.
Answer: Helium and iodine are non-metals.

Question 26. Name the compound formed when magnesium filament is burnt in oxygen.
Answer: When magnesium filament is burnt in oxygen, magnesium oxide (MgO) is formed.

Question 27. The formula of carbon dioxide is CO₂. What can you conclude from this?
Answer: We can say that each molecule of carbon dioxide contains one carbon atom and two oxygen atoms. The atomicity of CO₂ is 3.

Question 28. Give an example of a mixture where a gas is dissolved in a liquid.
Answer: Soda water or lemonade is a mixture where carbon dioxide gas is dissolved in water at high pressure.

Question 29. Mention one property of oxygen.
Answer: Oxygen is not combustible but supports combustion.

Question 30. Give the names of elements present in the compound called baking powder.
Answer: Baking powder or Sodium hydrogen carbonate (N_aHCO₃) contains sodium, hydrogen, carbon and oxygen.

Chapter 3 Element Compound And Mixture Qshort Answer Type Questions

Question 1. Water is a compound-explain why?
Answer: Water is a pure substance composed of two constituent elements. The constituent elements of water can not be separated by simple processes.

When electricity is passed through water, hydrogen and oxygen gases are produced following a definite volume and mass ratio.

Their properties are different from water. Hence water is not a mixture. It is a compound.

Class 6 Science Question Answer WBBSE

Question 2. What is a compound? Give example.
Answer: A compound is a pure substance, consisting of two or more elements, which are combined chemically in a definite proportion. Water, carbon dioxide etc. are compounds.

Question 3. What is the difference between Cl and CI₂?
Answer: Cl means an atom of chlorine in an uncombined state. Chlorine element is represented by Cl. CI2 is the formula of chlorine molecule.

It implies that in each chlorine molecule, two chlorine atoms are present (diatomic molecule).

Question 4. If lighted which will burn quickly-a big lump of coal or crushed coal of the same weight? Give
reasons.
Answer: Among the two, crushed coal will burn quickly. The surface area of crushed coal is much more than that of a lump of coal of the same weight.

More surface area makes it easy to combine with oxygen and thus making the burning process faster.

Question 5. When dissolved in water, sugar is no longer seen. Why?
Answer: A particle of sugar is composed of a very, very large number of smaller particles.

When dissolved in water, water breaks them apart and the smaller particles are so small that they are not visible through our naked eyes.

Question 6. Write two properties of hydrogen.
Answer: Two properties of hydrogen:
1. It is lighter than air.
2. Hydrogen is not a supporter of combustion, but it itself burns with a pale blue flame.

Question 7. How can you separate sugar from a sugar solution? What is the name of this process?
Answer: Sugar dissolves in water to form a homogeneous mixture. Let us take some amount of sugar solution in a beaker and boil it for some time.

As a result, some water will vapourize and the solution will become more concentrated.

If this concentrated solution is allowed to cool down undisturbed, solid sugar particles are separated from the solution. This process is known as crystallization.

Question 8. Mention the processes of separation of the constituting components from the following mixtures: (i) muddy water, and (ii) a mixture of sand and iron.
Answer:

1. The components of muddy water can be separated by using filtration. The solution is to be filtered through a filter paper.

The water will pass through the filter paper but the solid, insoluble mud particles will remain within the paper. So water is filtrate and mud is residue.

2. A mixture of sand and iron can be separated from one another by using a magnet.

When a magnet is brought near the mixture, it attracts the iron particles only. So the mixture becomes free from iron particles.

Question 9. What do you mean by valency? How can it be determined? Give a suitable example.
Answer: The number of hydrogen atoms that combine with one atom of a particular element to form a compound is called the valency of that element in that particular compound. The valency of hydrogen is assumed to be unity,1.

The formula of hydrogen sulphide is HS. In this case, one sulphur atom is combined with two hydrogen atoms in a molecule. So valency of sulphur in hydrogen sulphide is 2.

Class 6 Science Question Answer WBBSE

Question 10. Write the symbols of the following elements: nitrogen, beryllium, manganese, and gold.
Answer: Nitrogen: N; beryllium: Be; manganese: Mn; gold: Au.

Question 11. Name the elements present in each of the following compounds: sugar, salt, marble rock, and ice.
Answer:

Sugar: carbon, hydrogen, oxygen
Salt: sodium and chlorine
Marble rock: calcium, carbon, oxygen Ice: hydrogen, oxygen.

Question 12. Which of the following are compounds and which of the following are elements? Charcoal, salt, copper, sugar.
Answer: Compound: salt, sugar Element: copper, charcoal.

Question 13. Write the symbols of magnesium and helium.
Answer: The symbol of magnesium is Mg: and the symbol of helium is He.

Question 14. Write two general properties of metal. Or, How can you recognize a metal?
Answer: Metals have the following characteristics:
1. Metals have metallic lustre i.e. they have shining surfaces. Metals produce a sonorous (dong) sound when hit with a solid object.

2. Metals are usually good conductors of heat and electricity.

Question 15. In how many ways matter can be classified on the basis of their state? Name them.
Answer: A matter can be classified as solid, liquid or gas on the basis of its state.

Question 16. Define symbol and formula.
Answer: Symbol is the short form or abbreviated English name (and in some cases the Latin or German name) of an element.

The formula is a representation of a substance (elements or compounds) by means of symbols. It also denotes the number of atoms of each element present in one molecule of the substance.

Question 17. Write the symbol formula of the following: oxygen gas, carbon, carbon monoxide, ammonia, iron, and white phosphorous.
Answer: Oxygen gas: O₂ Carbon: C, Carbon monoxide: CO, Ammonia: NH₃, Iron: Fe,
White phosphorous: P4

Question 18. The formula of water is H2O. What information do you get from this?
Answer: From this formula, we find that two hydrogen atoms combine with one oxygen atom in a definite weight ratio. H₂O means one triatomic molecule of water.

Question 19. Give an example of one liquid metal and a non-metal which is a good conductor of electricity.
Answer: An example of a metal which is liquid at room temperature: Mercury.
Example of a non-metal which is a good conductor prime of electricity: Graphite.

Question 20. Write a short note on valency.
Answer: The number of hydrogen atoms that combine with one atom of a particular element to form a compound is called the valency of that element in that particular compound.

The valency of hydrogen is assumed to be unity, ie. 1.

The formula of hydrogen sulphide is H₂S. So in this case one sulphur atom is combined with two hydrogen atoms in a molecule.

Similarly, in methane (CH₄), one carbon atom is combined with 4 hydrogen atoms.

In ammonia (NH₃) one nitrogen atom is combined with three hydrogen atoms.

So valency of sulphur in hydrogen sulphide is 2; the valency of carbon in methane is 4; the valency of nitrogen in ammonia is 3.

Class 6 Science Question Answer WBBSE

Question 21. Write a short note on filtration.
Answer: This is a technique of separation of insoluble solute from a liquid solution. This is done by sieving.

The sieve has holes of a particular size. The size of the holes of the sieve should be smaller than the insoluble solid parties which are to be separated from the liquid solution.

The molecules of a liquid are so small that they can pass through the holes of the sieve. In the laboratory, we use filter paper as sieves.

The liquid which passes through the holes is called filtrate and the insoluble solute particles which remain on the filter paper are called residue. For the purification of water, a filter is used.

Question 22. Write the formula of phosphorous pentachloride and methane.
Answer: The formula of phosphorous pentachloride and methane are PCI₅, and CH_1, respectively.

Question 23. Write the symbol of the following elements: magnesium, chromium, silver, and boron.
Answer: The symbol of magnesium, chromium, silver and boron are Mg, Cr, Ag and B, respectively.

Question 24. What do you mean by crystallization?
Answer: Crystallization is a method of separation of a soluble solute from a liquid solution.

In this method, the liquid solution is boiled for some time so that most of the liquid solvent evaporates and the concentration of solute in the solution increases.

When this is kept undisturbed for some time, solid particles of solute separate from the solution.

Question 25. Write about the atomicity of S₈.
Answer: In S, there are 8 atoms of sulphur constituting a molecule. Hence the atomicity is 8.

Question 26. What is the difference between 2H and H₂?
Answer: The hydrogen element is represented by the symbol H. 2H means two atoms of hydrogen in an uncombined state.

H₂ represents one molecule of hydrogen. Each molecule of hydrogen contains two atoms of hydrogen. So its atomicity is 2.

Question 27. On a piece of white paper, you are given a mixture of tea and iron powder. How can you separate them?
Answer: Since one of the two components is a magnetic substance, they can be separated by using a magnet.

If a magnet is brought near the mixture, only iron powder is attracted to the magnet.

So the mixture becomes free from iron powder.

Question 28. What is the atomicity of white phosphorous, sodium, ozone and iodine?
Answer: Write the chemical formula of molecules of these elements.

The atomicity of white phosphorous, sodium, ozone and iodine are 4, 1, 3 and 2, respectively. Chemical formula: White phosphorus-P₄Sodium-Na, Ozone-03, Lodine-I₂

Question 29. Classify the following as metal or non-metal: gold, sulphur, zinc, copper, nitrogen, and graphite.
Answer: Metals: gold, zinc, copper Non-metals: sulphur, nitrogen, graphite.

Question 30. Air contains hydrogen and oxygen. When water is dissociated we get hydrogen and oxygen. Are both of them a mixture? Explain.
Answer: In air properties of both hydrogen and oxygen are retained. Their proportion varies from place to place. So air is a mixture.

But the properties of water are different from that of hydrogen and oxygen. Hydrogen and oxygen combine in a definite proportion to produce water.

We can not obtain gaseous hydrogen and oxygen from water by simple processes. So water is a compound.

Question 31. List two methods by which we can obtain pure salt from seawater. Which method is better and why?
Answer: Evaporation and crystallisation.
Crystallisation is the better method. It has the following advantages over the evaporation technique :
1. The salt obtained after evaporation is contaminated with other impurities but the crystals obtained are of pure substance only.

2. Some solids decompose on heating to dryness. This does not happen in crystallisation.

Class 6 Science Question Answer WBBSE

Question 32. Which separation technique would you apply for the separation of the following: (a) small pieces of metals from the engine oil of a car, (b) tea leaves from tea,(c) chalk powder from water, (d) stone dust from water
Answer:

1. Filtration

2. Filtration

3. Filtration

4. Sedimentation and Decantation

Question 33. Mention two differences between atoms and said molecules.
Answer:

Mixtures: Dust storm (mixture of dust and gases), tap water (mixture of water and impurities) and cooking gas (mixture of hydrocarbons like propane and butane).

Question 34. Identify compounds from the following: Marble, Dust storm, distilled water, tap water, and Cooking gas. Give reasons.
Compounds: Marble calcium carbonate (C_aCO), Distilled water (H₂O)

Chapter 3 Element Compound And Mixture Qlong Answer Type Questions

Question 1. Describe a process of separation of water and mud from muddy water.
Answer: Activity 11: Let us take some amount of muddy water. We want to separate the “mud”, which is an insoluble impurity present in water by filtration.

For this, we need a sieve. A filter paper is used for this purpose. Mud particles are small. But a filter paper has even smaller holes.

The shows the steps involved to fold a filter paper in the form of a cone. The cone-shaped folded filter paper is then placed on a funnel.

The muddy water is then poured into the filter paper. The molecules of water pass through the holes of the filter paper but the mud particles can’t. They remain on the filter paper.

The liquid which is coming out through the filter paper is in general called filtrate while the solid particles that remain on the filter paper are called residue.

 

 

Question 2. Write three differences between metal and non-metal.
Answer:

Question 3. Write the symbol of hydrogen and oxygen. Write the formula of the compound they form by combining with each other. Write the valency of oxygen in this compound. The symbol of hydrogen is H
Answer: The symbol of oxygen is O
The formula of the compound they form by combining with each other is water.

Its formula is H₂O. Here one oxygen is combined with two hydrogen atoms. So the valency of oxygen in water is 2.

Question 4. In relation to filtration, what do you mean by filtrate and residue? Which of the following mixtures can be separated into constituent components by filtration: sugar solution; oil and a pigment which is soluble in oil; the mixture of water and sand?
Answer: The filtration technique is used to separate insoluble solid solute from a liquid solution. This is done using sieves having a large number of holes.

The size of the holes is such that when such a solution is poured over the sieve, the solvent molecules can easily pass through.

School Science is called filtrate, while the bigger solute particles cannot pass through the holes and they remain on the sieve. They are called residues.

A mixture of water and sand can be separated from their mixture by filtration. This technique can be used for solutions where an insoluble, solid solute is present in a liquid.

For sugar solution, sugar is completely dissolved in water. For oil and a pigment which is soluble in oil, this technique cannot be used as the pigment is soluble in the solvent (oil).

Question 5. Name and write the symbol of one tetra-atomic molecule. Give the name and symbol of an element which can exhibit atomicity of both 2 and 3.
A metal ‘M’ forms a hydride having a chemical formula of MH2. What can you infer about the valency of the metal?
Answer: White phosphorus (P₄) is a tetra atomic molecule. Oxygen (O) shows atomicity of 2 (in O₂) and 3 (in O₃).

The valency of hydrogen is assumed to be unity, ie. 1. Since the metal M combines with two numbers of hydrogen atoms, hence the valency of the metal is 2 in MH₂.

Question 6. An element is sonorous and highly ductile. Under which category would you classify this element?
Name a non-metal which is known to form the largest number of compounds. Name a non-metal which is an absolute essential for combustion to happen.
Answer: Metals are sonorous and highly ductile. Hence the element must be metal.
Carbon forms the largest number of compounds.

Question 7. When a metal (A) is burnt in an atmosphere of it in an atmosphere of a colourless and odourless gas, a white powder (B) is formed. The gas is essential to carry out respiration. Identify A, B and the gas.
Answer: The metal

(1) is magnesium (Mg) and the gas is Oxygen (O₂).

Oxygen is colourless and odourless and it is essential for respiration. These compounds are classified under organic compounds. oxygen, it forms a white powdery substance

(2) called magnesium oxide (MgO).

Question 8. What will happen when current is passed through two iron nails placed inside acidulated water taken in a beaker? Which gases will evolve from the nails connected to the battery terminals?
Answer: When electricity is passed through acidulated water (water with lime juice), water undergoes electrolytic dissociation to form hydrogen and oxygen.

This is called the electrolysis of water. It shows that the compound called water (H₂O) is composed of two constituent elements of hydrogen (H₂) and oxygen (O₂).

Oxygen is the non-metal which is required for combustion.

planning brs When magnesium is burnt in an atmosphere Hydrogen gas shall evolve from the iron nail connected to the negative terminal of the Un battery (acting as cathode) and oxygen gas shall evolve from the iron nail connected to the positive terminal of the battery (acting as anode).

Chapter 12 Waste Products Review Questions Environment Review Questions MCQs

Question 1. The following waste is not from households.

1. Plastic
2. Glass
3. Methane
4. Paper

Answer: 3. Methane

Question 2. The following waste is not biodegradable in nature.

1. Paper
2. Plastic
3. Vegetable Waste
4. Animal hide

Answer: 2. Plastic

Read And Learn More: WBBSE Solutions For Class 6 School Science

Question 3. The E-waste from a television set contains

1. Lead
2. Mercury
3. Cadmium
4. All of them

Answer: 4. All of them

Question 4. Leather industry waste includes

1. Cadmium
2. Nickel
3. Chromium
4. Cobalt

Answer: 3. Chromium

Question 5. Building waste may contain

1. Sand
2. Cement
3. Both
4. Plastic

Answer: 3. Both

Question 6. Solid waste includes

1. Metal
2. Glass
3. Paper
4. All Of Them

Answer: 4. All Of Them

Question 7. The bio-plastic is so-called because

1. It Is Produced By Biological Organism
2. It Is Biodegradable
3. Both
4. None

Answer: 3. Both

Question 8. Organic solvent includes

1. Water
2. Benzene
3. Both
4. None

Answer: 2. Benzene

Question 9. Pulper is the other name of

1. Glass grinder
2. Stone grinder
3. Paper grinder
4. Stone crusher

Answer: 3. Paper grinder

Question 10. Cullet is the other name for small pieces of

1. Glass
2. Metal
3. Pebbles
4. Cardboard

Answer: 1. Glass

Question 11. An ingot is the other name for molten

1. Iron
2. Cadmium
3. Aluminium
4. Calcium

Answer: 3. Aluminium

Question 12. The common ingredients of cement is

1. Chromium
2. Calcium
3. Iron
4. Aluminium

Answer: 2. Calcium

Question 13. Recycling of metals involves

1. Collection
2. Melting
3. Rolling
4. All Of Them

Answer: 4. All Of Them

Question 14. The approximate time required for recycling aluminium is

1. 15 days
2. 30 days
3. 45 days
4. 60 days

Answer: 4. 60 days

Question 15. Recycling plastic makes it

1. Black
2. Blue
3. Both
4. White

Answer: 3. Both

Question 16. If one refuses a plastic carry bag from the shop, indicate which of the 4R system does it belong to?

1. Reduce
2. Reuse
3. Recycle
4. Refuse

Answer: 4. Refuse

Question 17. DDT is released into nature from

1. Households
2. Factories
3. Agricultural fields
4. Ponds

Answer: 3. Agricultural fields

Question 18. Which one is not possible to be recycled?

1. Iron
2. Aluminium
3. Computer
4. Rotten vegetables

Answer: 4. Rotten vegetables

 

Chapter 12 Waste Products Fill In The Blanks

Question 1. Biodegradable waste is degraded by __________ and __________.
Answer: Bacteria, Fungi

Question 2. The commercial cans are made of __________.
Answer: Aluminium

Question 3. Cement mostly includes salts of __________.
Answer: Calcium

Question 4. Loss of resources can be prevented by __________.
Answer: Recycling

Question 5. Pulping is carried out for recycling of __________.
Answer: Paper

Question 6. Solid waste may be used in __________.
Answer: Landfill

Question 7. Recycling of metal involves a cycle of __________.
Answer: 60 days

Question 8. Rolling of metal will make them into __________.
Answer: Sheet

Question 9. Benzene is an __________ waste.
Answer: Organic

Question 10. Metals are drawn into a sheet by __________.
Answer: Rolling

Question 11. The paper grinding machine is also called __________.
Answer: Vat or pulper

Question 12. Television sets may release high amounts of __________ metals.
Answer: Heavy

Question 13. Long organic plant materials are also called __________.
Answer: Fibres

Question 14. Biodegradable plastics are degraded by __________ enzymes.
Answer: Bacterial

Question 15. Liquid aluminium is also called __________.
Answer: Ingots

 

Chapter 12 Waste Products Identify As True Or False

Question 1. WEEE is organic waste.
Answer: False

Question 2. Methane is a greenhouse gas.
Answer: True

Question 3. Metals are recycled after rolling.
Answer: True

Question 4. Bio-plastics are generated by fungi.
Answer: False

Question 5. Paper is biodegradable waste.
Answer: True

Question 6. Pulper is used for plastic recycling.
Answer: False

Question 7. Virgin plastic is white in colour.
Answer: True

Question 8. Municipal waste is mostly mixed in nature.
Answer: True

Question 9. Plastic pollution can kill soil-borne microbes.
Answer: True

Question 10. Liquid iron is called an ingot.
Answer: False

Question 11. Calcium is used in the making of cement.
Answer: True

Question 12. Recycling results in the loss of resources.
Answer: False

Question 13. DVD players may have heavy metals.
Answer: False

Question 14. Benzene is an organic solvent.
Answer: True

Question 15. Building material waste is organic in nature.
Answer: False

 

Chapter 12 Waste Products Match The Columns

 

Answer: A-5, B-4, C-1,D-2

 

Answer: A-4, B-3, C-1, D-5

 

Chapter 12 Waste Products Answer In Words Or A Sentence

Question 1. What is the term given to the accumulation of excess waste?
Answer: Pollution.

Question 2. Name two greenhouse gases.
Answer: Carbon dioxide and methane.

Question 3. Name the organism producing bio-plastic.
Answer: Bacteria.

Question 4. Which waste is used in the landfill?
Answer: Solid waste

Question 5. Name two heavy metals.
Answer: Mercury and cadmium.

Question 6. Name the heavy metal released from the tannery.
Answer: Chromium.

Question 7. Name two building wastes.
Answer: Sand and cement chunks.

Question 8. State the duration of the metal recycling cycle.
Answer: 60 days.

Question 9. Name the metal that is mostly recycled globally.
Answer: Aluminium.

Question 10. State the colour of the virgin plastic.
Answer: White.

Question 11. What type of waste is a gunny bag?
Answer: It is a biodegradable waste.

Question 12. Give an example of waste that is generated by the hospitals.
Answer: Used syringes/blood-stained gloves.

 

Chapter 12 Waste Products Short Answer Type Questions

Question 1. What is pollution?
Answer: Accumulation of waste products in excess in nature is called pollution.

Question 2. What is municipal waste?
Answer: Municipal waste is a mixture of biodegradable and non-biodegradable waste which is generated from households, schools, colleges, offices, marketplaces, restaurants etc.

Question 3. What is meant by automobile end-of-life waste?
Answer: It is the waste product generated from used cars.

After the car has been used to its fullest extent, it is sent to a scrapyard, the recyclable materials are recycled, but the products which are not suitable for recycling are crushed and may be sent to a landfill.

Though in India, the materials are always recycled.

Question 4. What do you mean by the 4R process of waste management?
Answer: The 4R process (Reduce, Reuse, Recycle, Refuse) is a systematic waste management process that consists of the collection, transportation and proper disposal of garbage, sewage and other waste products including offering various solutions for recycling the items and putting the waste to productive use for sustainability.

Question 5. What is meant by repulping?
Answer: The waste papers are shredded into small pieces, taken in a vat and heated at high temperature to melt the organic compound and they are removed from the pulp.

Question 6. What is meant by drinking?
Answer: The ink glue or any other sticky substance adhering to the paper pulp is removed by thorough washing, as a result of which the pulp is ideal for the manufacturing of recycled paper.

Question 7. What is meant by virgin pulp?
Answer: The virgin pulp in the fresh pulp is made from soft plant material, it is used in the making of fresh paper and also sometimes mixed with the used paper pulp after bleaching to brighten up its colour.

Question 8. What is meant by bio-plastic?
Answer: The biodegradable plastic produced within bacterial cells is called bio-plastic. It is degraded completely in the long run with the help of bacterial enzymes.

Question 9. What is meant by cullet?
Answer: The glass is purified from impurities like plastic, cork etc., and it is then crushed into small pieces with the help of a crusher, to be reused again for the manufacturing of glass.

Small pieces of clear glass are called cullet.

Question 10. How aluminium cans are prepared for recycling?
Answer: The cans are cleared of impurities, the associated iron or steel pieces are removed with the help of a big magnet and thus it is ready for getting melted and rolled.

Question 11. What are the main benefits of resource recycling?
Answer: The resources are saved by recycling, hence it is good for the economy of the country.

The pollution from the waste material is prevented, hence it is good for the environment. Finally, it saves the energy involved in the processing of the waste.

 

Chapter 12 Waste Products Long Answer Type Questions

Question 1. How are waste products classified on the basis of the waste generated?
Answer:

On the Basis of the Source

On the basis of source, waste materials can be classified into 7 different types as detailed below:

1. Municipal waste:

This includes trash or garbage from households, schools, offices, marketplaces, restaurants and other public places.

They include everyday items like food debris, used plastic bags, soda & soft drink cans and plastic water bottles, broken furniture, grass clippings, product packaging, broken home appliances and clothing.

2. Medical/Clinical waste:

Medical/clinical waste normally refers to waste produced by healthcare facilities, such as hospitals, clinics, surgical theatres, veterinary hospitals and laboratories.

They tend to be classified as hazardous waste rather than general waste. Items in this group include surgical items, pharmaceuticals, blood, body parts, wound dressing materials, needles and syringes.

 

 

3. Agricultural waste:

Typically, this is waste generated by agricultural activities. These vegetable peels, old blades, rotten food items, old electronic items etc.

These include horticulture, fruit growing, seed growing, livestock breeding, markets, gardens and seedling nurseries.

Waste items in this group include empty pesticide containers, old silage wrap, out-of-date medicines and wormers, used tyres, surplus milk, cocoa pods and corn husks.

4. End-of-life Automobiles:

When cars stop working, where do they end up? Many people just leave them to rust in the fields, but there is a better way to deal with them.

In many cities, these vehicles are sent to the plant, where all the removable parts are taken out for recycling.

The rest is flattened up and shredded into pieces for recycling. The last bits that cannot be used again are sent to a landfill.

5. Industrial waste:

Since the Industrial Revolution, the rise in the number of industries manufacturing glass, leather, textile, food, electronics, plastic and metal products has significantly contributed to waste production.

Take a look at the things in your home, every item was manufactured and one day it will be of no use, and waste will be produced as a result.

6. Construction/demolition waste:

Construction waste is that resulting from the construction of roads and buildings. Sometimes old buildings and structures are pulled down (demolished) to make space for new ones.

This is particularly common in old cities, that are undergoing modernization. This is called demolition waste.

Waste items include concrete debris, wood, earth, huge package boxes and plastics from the building materials etc.

7. Electronic or e-waste:

This is waste from electronic and electrical devices. Think of DVD and music players, TV, telephones, computers, vacuum cleaners and all the other electrical stuff in your home.

These are also called e-waste, e-scrap, or waste electrical and electronic equipment (WEEE). Some e-waste (like TV) contains lead, mercury, cadmium, and brominated flame retardants.

These are TIS harmful to humans and the environment. It is therefore important that the right authorities ensure the proper disposal of such waste.

Question 2. How is waste classified on the basis of physical properties?
Answer:

On the Basis of Physical Nature

On this basis, the waste material can be classified as solid waste, liquid waste and gaseous waste.

1. Solid waste:

Solid wastes include metallic and non-metallic waste including plastic, glass, and paper, which are disposed of in a landfill or maybe incinerated at high temperatures.

2. Liquid waste:

They include water-soluble compounds, or simply organic solvents. If these are added to a water body, it causes water pollution and reduces the oxygen level of the water body.

3. Gaseous wastes:

These are oxides of carbon, sulphur, nitrogen, several toxic hydrocarbons, aerosols, methane and green. house gases like CFC (chlorofluorocarbon). These are largely emitted from factories, chemical plants, vehicles etc.

Question 3. How is waste classified on the basis of degradable properties?
Answer:

On the Basis of Degradational Ability

On this basis, the waste products can be classified as non-biodegradable and biodegradable.

1. Non-biodegradable waste:

This waste product cannot be recycled by the normal microbial degradational process, it includes plastic, heavy metals etc.

2. Biodegradable waste:

These materials. include household products which may be vegetables or cooked food materials that are easily degraded by microbes. It also includes agricultural waste.

Question 4. What is waste management? State the principles of waste reduction.
Answer:

Waste Management

It is the collection, transport and disposal of garbage, sewage and other waste products.

Waste management encompasses the management of all processes and resources for proper handling of waste materials, maintenance of waste, and transportation by trucks and dumping facilities in compliance with health codes and environmental regulations.

The four principles (4R process) of waste reduction are Reduce, Reuse, Recycle, and Refuse.

 

 

1. Reduce:

Those waste products which increase garbage in our environment should be reduced on day to day basis, for example, plastic bags, thermal, plastic bottles etc.

2. Reuse:

Reusing the waste materials instead of discarding them, for example, vegetable peels, rechargeable batteries, etc.

3. Recycle:

This involves making new useful products from waste products, for example, plastic toys, old iron, glass materials, papers, aluminium, etc.

4. Refuse:

People should learn to refuse to accept such materials which would eventually produce non-biodegradable

 

Question 5. How is waste paper recycled?
Answer:

Paper waste:

Paper waste items include books, newspapers, magazines, cardboard boxes and envelopes.

 

 

Recycling of Paper Waste:

1. Collection, transportation and storage:

The biggest task for paper recycling companies probably includes the collection, transporting and sorting of waste paper.

This is because we always add paper to other waste items and get them contaminated with food, plastic and metals.

Sometimes collected paper is sent back to the landfills because they are too contaminated to use.

Waste paper should be kept in separate grades at home or in the office, for example, newspapers and corrugated boxes should not be mixed.

All paper recovered is sent to the recycling centre, where it is packed, graded, put into bales and sent to the paper mill. At the mill, all the paper is stored in a warehouse until it is needed.

2. Repulping and Screening:

From the storage shelves, they are moved into a big paper grinding machine called a vat (pulper).

Here the paper is chopped into tiny pieces, mixed with water and chemicals and heated up to break it down into organic plant material called fibre.

After that, it is screened to remove contaminants such as bits of plastic and globes of glue.

3. Deinking:

This involves ‘washing’ the pulp with chemicals to remove printing ink and glue residue. Sometimes, a process called floatation is applied to further remove got stubborn stains and sticky substances.

Floatation involves the use of chemicals not and air to create bubbles, which absorb the art stickies in the pulp.

4. Refining, Bleaching and Colour Stripping:

Refining involves beating the recycled pulp to make them ideal for paper-making.

After refining, additional chemicals are added to the bay to remove any dyes from the paper. It is then bleached to whiten and brighten it up.

5. Papermaking:

At this stage, the pulp is ready to be used for manufacturing paper. Sometimes new pulp (virgin pulp) is added to give it extra strength and smoothness.

Water is added to the pulp and sprayed onto a large metal screen in continuous mode. The water is drained on the screen and the fibres begin to bond with each other.

As it moves through the paper-making machines, press rollers squeeze out more water, heat them dry and coat them up. They are then finished into rolls.

Question 6. How is the recycling of glass carried out?
Answer:

Glass waste:

All glass products like broken bottles, beer and wine bottles can be recycled.

1. Recycling of Glass:

Recycling glass starts in your home. There is a reason why many 916 local councils provide different containers for green, brown, plain glass and even glass hot from broken windows.

The reason is that they are all made very differently and mixing them can create huge problems at the recycling centre.

 

 

2. Collection:

Many cities have collection spots. Trucks may also pick them up from your home, or you may be required to drop them off at a point in your town.

In all cases, try to do what the authorities have suggested. So, be sure you know the various glass types that are collected from your home.

They are washed and separated into the required grades for collection.

3. Cleaning and Crushing:

The glass is transported to the processing plant, where contaminants such as metal caps and plastic sleeves are removed.

Different grades are treated separately. Clean glass is then crushed into small pieces called cullet. Cullet is in high demand from glass manufacturers.

It melts at a lower temperature and it is cheaper than raw glass materials.

4. Ready for use:

The cullet is then transported to glass-making factories. Here, it is mixed with sand, soda ash and limestone.

It is heated at a very high temperature and melted into liquid glass. This liquid is then poured into moulds that give glass its shape.

Glass is used for many things, depending on what grade they were recycled from. A few items made of recycled glass include fibre-glass, countertops, bottles and jars.

 

Question 7. How is the recycling of aluminium carried out?
Answer:

4. Aluminium waste:

Cans from soda drinks, tomatoes, fruit cans and all other cans can be recycled.

When these are collected, they are sent to the recycling unit, where all the waste from each type is combined, crushed, melted and processed into new materials.

 

 

1. Aluminium recycling:

In recent times, there has been a massive improvement in recycling aluminium cans. Those cans, hoil-placed end-to-end, could make 171 circles around the earth.

Every minute, an average of 105,800 aluminium cans are recycled. It is clear that can recycling is very important in the present life.

2. Collection:

People may use special cans. recycling containers (bins) that are clearly marked. This helps people to know what to place in them.

Can include soda, fruit and vegetable cans. Trucks come for these at pick-up spots at the recycling centres. Cans may also be metallic or steel, but usually, common people do not know the difference.

3. Preparation:

At the collection centre, a huge magnet is rolled over them as they move on the conveyor belt to pull out all the metal and steel cans.

Only the aluminium cans are washed, crushed, and condensed into 30 pounds. briquettes for other companies for further processing. The rest is also sorted and sent to their appropriate recycling centres.

4. Melting:

The crushed cans are loaded into a burning furnace, where all printing and designs on the cans are removed, melted and blended with new (virgin) aluminium.

The molten (liquid) aluminium is poured into moulds and made into bars called ingots.

5. Sheets:

The ingots are then fed into powerful rollers, which flatten them into. thin sheets of aluminium. These thin sheets are rolled into coils and sold or sent to can-making factories.

They use aluminium coils to prepare cans and containers for other food and drink manufacturers.

It is estimated that cans collected at collection points take up to 60 days to reappear in the shops again as new cans containing your favourite soda, juice or food.

 

Question 8. Give examples to show how the 4R process can be followed in households to minimize pollution of surrounding localities.
Answer: Every citizen should implement the 4R process of waste management in his/her household for a sustainable environment.

Reduce:

Vegetable peels may be fed to cows. Leftover kitchen waste or semi-rotten cooked fish/meat may be fed to crows.

Reuse:

Carry bags (plastic or jute or cloth) may be used time and again when somebody goes to the market or local shop for buying products. Gift wrappers may be reused instead of discarding them after one time use.

Recycle:

Kitchen waste, vegetable peels, leaves etc may be dumped in a pit in the garden to prepare good quality compost fertiliser.

Refuse:

Everyone should be conscious enough to refuse plastic carry bags from local shops or supermarkets to minimize their accumulation and associated pollution.

Chapter 11 Habits And Habitats Of Some Important Animals MCQs

Behavioural Science And Behavioural Scientists Review Questions Environment Review Questions 

Question 1. Behavioural science deals with the behaviour of

1. Animals
2. Human and animals
3. Human only
4. Living organisms.

Answer: 2. Human and animals

Question 2. The study of animal behaviour is known as

1. Ecology
2. Psychology
3. Aetiology
4. Biology

Answer: 3. Ethology

Read And Learn More: WBBSE Solutions For Class 6 School Science

Question 3. Tinbergen, Lorenz, and Frisch were awarded the Nobel Prize in

1. 1973
2. 1790
3. 2010
4. Not awarded Nobel prize

Answer: 1. 1973

Question 4. The founder of modern ethology is

1. Hess
2. Darwin
3. Lorenz
4. Spalding

Answer: 3. Lorenz

Question 5. Ethology came to be considered an independent branch of zoology around

1. 1947
2. 1900
3. 2000
4. 1910

Answer: 4. 1910

Question 6. Darwin proposed the theory of

1. Behaviour
2. Evolution
3. Psychology
4. Aetiology

Answer: 2. Evolution

Question 7. Niko Tinbergen was an

1. Ethologist
2. Ornithologist
3. Zoologist
4. All the above are correct

Answer: 4. All the above are correct

Question 8. Konrad Lorenz worked on

1. Goose
2. Dogs
3. Cats
4. Seals

Answer: 1. Goose

Question 9. Bee dance language was interpreted by

1. Darwin
2. Tinbergen
3. Frisch
4. Lorenz

Answer: 3. Frisch

Question 10. Jane Goodall studied the behaviour of

1. Wild dogs
2. Tigers
3. Ducks
4. Chimpanzees

Answer: 4. Chimpanzees

Question 11. Ornithologist Salim Ali was a/an

1. Pakistani
2. Indian
3. Bangladeshi
4. European

Answer: 2. Indian

Question 12. Raghavendra Gadagkar is associated with

1. Bose Institute
2. Saha Institute
3. Indian Institute of Science
4. British Museum

Answer: 3. Indian Institute of Science

Question 13. Gopal Chandra Bhattacharya got

1. Rabindra Purashkar
2. Bankim Purashkar
3. Nobel Prize
4. None of the above

Answer: 1. Rabindra Purashkar

Question 14. R.L. Brahmachari was a recipient of

1. Rabindra Purashkar
2. Bankim Purashkar
3. Nobel Prize
4. None of the above

Answer: 4. Rabindra Purashkar

 

Chapter 11 Habits And Habitats Of Some Important Animals Behavioural Science And Behavioural Scientists Fill In The Blanks

Question 1. Behavioural science is the systematic analysis and investigation of __________ and animal behaviour.
Answer: Human

Question 2. The study of animal behaviour is known as __________.
Answer: Ethology

Question 3. Darwin’s famous book is On the Origin of Species by Means of __________ Selection.
Answer: Natural

Question 4. Jean Henri Fabre was a __________ entomologist.
Answer: French

Question 5. Tinbergen shared Nobel Prize with Frisch and __________.
Answer: Lorenz

Question 6. Karl von Frisch was a zoologist who studied communication among __________.
Answer: Bees

Question 7. Jane Goodall set out to Tanzania to study wild __________.
Answer: Chimpanzees

Question 8. __________ was an Indian ornithologist and naturalist.
Answer: Salim Ali

Question 9. __________ is a professor at the Centre for Ecological Sciences, Indian Institute of Science in Bangalore.
Answer: Gadagkar

Question 10. R.L. Brahmachary is a pioneer in __________ pheromone research.
Answer: Tiger

Question 11. Gopal Chandra Bhattacharya was an Indian __________ and naturalist.
Answer: Entomologist

 

Chapter 11 Habits And Habitats Of Some Important Animals Behavioural Science And Behavioural Scientists Identify As True Or False

Question 1. Behavioural science is the systematic analysis and investigation of human and animal behaviour.
Answer: True

Question 2. Ethology has existed as a concept since 1762 when it was defined in France as the study of animal behaviour.
Answer: True

Question 3. The modern discipline of ethology is generally considered to have begun during the 1830s.
Answer: False

Question 4. The founder of modern ethology is Darwin.
Answer: False

Question 5. Tinbergen embarked on a five-year survey voyage around the world on the HMS Beagle.
Answer: False

Question 6. Darwin proposed that instincts were behavioural adaptations that had evolved by natural selection.
Answer: True

Question 7. Fabre did important research on the behaviour of chimpanzees.
Answer: False

Question 8. Tinbergen established European ethology as the study of the behavioural patterns of animals.
Answer: True

Question 9. Konrad Lorenz was an Indian zoologist and founder of modern ethology.
Answer: False

Question 10. Karl von Frisch was a zoologist who studied communication among birds.
Answer: False

Question 11. Goodall noted that chimps have a complex social system.
Answer: True

Question 12. Salim Ali is referred to as the “birdman of India”.
Answer: True

 

Chapter 11 Habits And Habitats Of Some Important Animals Behavioural Science And Behavioural Scientists Match the Column

 

Answer: A-4, B-3, C-5, D-1

 

Answer: A-2, B-5, C-1, D-4

Chapter 11 Habits And Habitats Of Some Important Animals Behavioural Science And Behavioural Scientists Answer In Words Or A Sentence

Question 1. Which science is the systematic analysis and investigation of human and animal behaviour? Answer: Answer: Behavioural science.

Question 2. What is ethology?
Answer: Ethology is the study of animal behaviour.

Question 3. In which year Tinbergen was awarded the Nobel prize?
Answer: 1973.

Question 4. In which year Darwin’s famous book was published?
Answer: 1859.

Question 5. Karl von Frisch decoded the language of which insects?
Answer: Honey bees.

Question 6. Who is considered as ‘birdman of India’?
Answer: Salim Ali.

Question 7. Who has written the book “Survival Strategies”?
Answer: Raghavendra Gadagkar.

Question 8. Who wrote the book “Banglar Kitpatanga”?
Answer: Gopal Chandra Bhattacharya.

Question 9. Identify the odd man out:
Answer: Salim Ali, Gopal Chandra Bhattacharya, Bernoulli, Konrad Lorenz.
Bernoulli: He was a physicist while other people were behavioural scientists.

Question 10. Name the first woman behavioural scientist.
Answer: Valerie Jane Goodall.

 

Chapter 11 Habits And Habitats Of Some Important Animals Behavioural Science And Behavioural Scientists Short Answer Type Questions

Question 1. What is behavioural science?
Answer: Behavioural science is the systematic analysis and investigation of human and animal behaviour through controlled and naturalistic observation and disciplined scientific experimentation.

Examples of behavioural sciences include psychology, psychobiology, criminology and cognitive science.

Question 2. State the origin and development of ethology.
Answer: Ethology has its scientific roots in the work of Charles Darwin and of American and German ornithologists of the late 19th and early 20th century, including Charles O.

Whitman, Oskar Heinroth, and Wallace Craig. The modern discipline of ethology is generally considered to have begun during the 1930s with the work of Dutch biologist Nikolaas Tinbergen and Austrian biologist Konrad Lorenz and Karl Von Frisch, joint awardees of the 1973 Nobel Prize in Physiology or Medicine.

Question 3. Write about Darwin’s contribution to ethology.
Answer: Darwin proposed that instincts were behavioural adaptations that had evolved by natural selection.

Darwin provided many examples of instinctive behaviours in animals and suggested how such behaviours could have evolved.

He explained the roles that emotions play in the biology of animals and extended those explanations to humans.

Question 4. Write about Tinbergen’s contribution to behavioural science.
Answer: Tinbergen emphasized the importance of both instinctive and learned behaviour to survival and used animal behaviour as a basis for speculations about the nature of human violence and aggression.

He is especially well known for his long-term observations of seagulls, which led to important generalizations on courtship and mating behaviour.

Question 5. Write about Karl von Frisch’s study of bee behaviour.
Answer: Frisch established that bees, through their perception of polarized light, use the Sun as a compass.

He also found that they are capable of using this method of orientation when the Sun is not visible, apparently remembering patterns of polarization presented by the sky at different times of the day and the location of previously encountered landmarks.

Question 6. Write about an Indian ornithologist.
Answer: Abdul Ali was an Indian ornithologist and naturalist.

Sometimes referred to as the “birdman of India”, Salim Ali was among the first Indians to conduct systematic bird surveys across India and several bird books that he wrote helped popularize ornithology in India.

Question 7. Write about a natural biologist of Bengal.
Answer: Gopal Chandra Bhattacharya (1 August 1895- 8 April 1981) was an Indian entomologist and naturalist. One of his monumental works was the book “Banglar Kitpatanga”.

Credited with popularizing science in Bengal, he is best known for his studies in insects and metamorphosis.

 

Chapter 11 Habits And Habitats Of Some Important Animals Behavioural Science And Behavioural Scientists Short Long Answer Type Questions

Question 1. Write briefly about the history of behavioural science
Answer:

History of Behavioural Science

Ethology has existed as a concept since 1762 when it was defined in France as the study of animal behaviour.

In this sense, it carries the same meaning as the Greek word “ethos”, from which the modern term ethology is derived.

Many naturalists have studied aspects of animal behaviour throughout history.

Ethology has its scientific roots in the work of Charles Darwin and of American and German ornithologists of the late 19th and early 20th century, including Charles O.

Whitman, Oskar Heinroth and Wallace Craig.

The modern discipline of ethology is generally considered to have begun during the 1930s with the work of Dutch biologist Nikolaas Tinbergen and Austrian biologists Konrad Lorenz and Karl von Frisch, joint awardees of the 1973 Nobel Prize in Physiology or Medicine.

Ethology is a combination of laboratory and field science with a strong relation to some other disciplines such as neuroanatomy, ecology, and evolutionary biology.

Ethologists are typically interested in a behavioural process rather than in a particular animal group, and often study one type of behaviour, such as aggression, in a number of unrelated animals.

Ethology is a rapidly growing field. Since the dawn of the 21st century, many aspects of animal communication, emotions, culture, learning and sexuality that the scientific community long thought it understood have been re-examined, and new conclusions reached.

New fields, such as neuroethology, have developed. Understanding ethology or animal behaviour can be important in animal training.

Considering the natural behaviours of different species or breeds enables the trainer to select the individuals best suited to perform the required task.

It also enables the trainer to encourage the performance of naturally occurring behaviours and also the discontinuance of undesirable behaviours.

The founder of modern ethology is Konrad Z. Lorenz, a physician, zoologist, and comparative anatomist. By systematic application of biological research methods to the analysis of animal behaviour, he provided the initial.

impetus in the 1930s. The first modern ethology textbook, The Study of Instinct, was written by Nikolaas Tinbergen in 1951. E. H. Hess (1962) and Eibl-Eibesfeldt (1966) produced summaries of the modern concepts of behaviour.

The observations of a number of pioneers, including Spalding (1873), Darwin (1872), Whitman (1898), Altum (1868), Heinroth (1911), and Craig (1918), awakened scientific interest in animal behaviour, and ethology came to be considered an independent branch of zoology around 1910.

 

Question 2. Write about any two behavioural biologists.
Answer:

Some Notable Behavioural Scientists

1. Charles Robert Darwin:

Naturalist Charles Darwin was born in Shrewsbury, England, on February 12, 1809. In 1831, he embarked on a five-year survey voyage around the world on the HMS Beagle.

His studies of specimens around the globe led him to formulate his theory of evolution and his views on the process of natural selection.

On November 24, 1859, he published a detailed explanation of his theory in his best-known work, On the Origin of Species by Means of Natural Selection. He died on April 19, 1882, in London.

Darwin proposed that instincts were behavioural adaptations that had evolved by natural selection.

Darwin provided many examples of instinctive behaviours in animals and suggested how such behaviours could have evolved.

He explained the roles that emotions play in the biology of animals and extended those explanations to humans.

2. Jean Henri Fabre:

Jean Henri Fabre (December 22, 1823- October 11, 1915) was a French entomologist, famous for his study of the anatomy and behaviour of insects.

Largely self-taught, Fabre began his career as a Physics teacher at Carpentras (France). From his youth, he was attracted by the beauty of butterflies and grasshoppers.

Fabre did important research on the insect of bees, wasps, beetles, grasshoppers and crickets.

Based on his observations of the paralyzing actions of wasps in response to stimulating zones in their prey, he described the importance of inherited instinct as a behaviour pattern in insects.

Although Fabre never accepted the theory of evolution, his work was respected by Darwin.

Chapter 11 Habits And Habitats Of Some Important Animals The Habits And Behaviour Of Some Animals Review Questions Environment Review Questions MCQ

Question 1. In ethology, habit usually refers to the behaviour of

1. Animals
2. Birds
3. Human
4. Plants

Answer: 1. Animals

Question 2. The drones of ants are

1. Insects
2. Females
3. Males
4. Workers

Answer: 3. Males

Question 3. Black ants are fairly

1. Docile
2. Aggressive
3. Harmful
4. Dangerous

Answer: 1. Docile

Question 4. Ants, termites and honey bees are

1. Very useful
2. Very harmful
3. Eusocial
4. None of the above

Answer: 3. Eusocial

Question 5. The process of worker termites feeding other nestmates is known as

1. Prophylaxis
2. Nutrition
3. Test maker
4. Trophallaxis

Answer: 4. Trophallaxis

Question 6. The scientific name of the Indian honey bee is Apis

1. Dorsata
2. Indica
3. bengalensis
4. Florea

Answer: 2. Indica

Question 7. Worker bees are

1. Males
2. Females
3. Queens
4. Drones

Answer: 2. Females

Question 8. Honey bees live in a nest called a

1. Dormitory
2. House
3. Den
4. Hive

Answer: 4. Hive

Question 9. Honey bees eat nectar and pollen from

1. Flowers
2. Plants
3. Trees
4. Basket

Answer: 1. Flowers

Question 10. Bees communicate by a mode of

1. Language
2. Pheromone
3. Dance
4. Sound

Answer: 3. Dance

Question 11. Worker bees have a stinger which is sharp

1. Hook like
2. Rodlike
3. Tail like
4. Needle-like

Answer: 1. Hook like

Question 12. The Asian elephant is

1. Loxodonta africana
2. Elephas maximus
3. Apis indica
4. Pan paniscus

Answer: 2. Elephas maximus

Question 13. Elephant feed on plants and hence are

1. Omnivorous
2. Vegivorous
3. Carnivorous
4. Herbivorous

Answer: 4. Herbivorous

Question 14. Elephants are considered to be

1. Endangered species.
2. Endemic species
3. Keystone species
4. They are not species

Answer: 3. Keystone species

Question 15. The homeland of chimpanzees is

1. India
2. Africa
3. Europe
4. America

Answer: 2. Africa

Question 16. Bonobos are a type of

1. Elephants
2. Cats
3. Chimpanzee
4. Lions

Answer: 3. Chimpanzee

Question 17. Young chimps stay with their mothers for up to

1. 2 years
2. 10 years
3. 1 year
4. 20 years

Answer: 2. 10 years

Question 18. Santragachhi Jheel in West Bengal is famous for

1. Migratory birds
2. Tiger
3. Swimming pool
4. All the above

Answer: 1. Migratory birds

Question 19. Crows belong to the genus

1. Kaw
2. Croooaaak
3. Raven
4. Corvus

Answer: 4. Corvus

Question 20. The word ‘Mosquito’ is derived from

1. English
2. Greek
3. Spanish
4. Hindi

Answer: 3. Spanish

Question 21. Malaria is spread by

1. Air
2. Water
3. Food
4. Mosquito

Answer: 4. Mosquito

Question 22. The mosquitos which suck blood are

1. Females
2. Males
3. Anopheles
4. Culex

Answer: 1. Females

Question 23. Fishes are

1. Vertebrates
2. Aquatic
3. Lung bearing
4. ‘1’ and ‘2’ correct

Answer: 4. ‘1’ and ‘2’ correct

Question 24. In sea horses, parental care is performed by

1. Females
2. Males
3. ‘a’ and ‘b’ correct
4. None

Answer: 2. Males

Question 25. Snakes are

1. Reptiles
2. Insects
3. Mammals
4. Invertebrates

Answer: 1. Reptiles

Question 26. The largest cat species is

1. Wild cat
2. Lion
3. Tiger
4. Elephant

Answer: 3. Tiger

Question 27. Tigers are

1. Solitary
2. Colonial
3. Gregarious
4. Parasites

Answer: 1. Solitary

Question 28. Whales are

1. Fishes
2. Sharks
3. Dolphins
4. Mammals

Answer: 4. Mammals

Question 29. Baleen whales have no

1. Teeth
2. Lungs
3. Gills
4. ‘1’ and ‘3’ correct

Answer: 4. ‘1’ and ‘3’ correct

Question 30. Termites feed on

1. Rice
2. Cellulose
3. Other insects
4. None of these

Answer: 2. Cellulose

Question 31. The most intelligent and is

1. Red ants
2. Black ants
3. Peasant ants
4. Nomadic ants

Answer: 2. Black ants

Question 32. Which of the following diseases is not spread through mosquitoes?

1. Malaria
2. Dengu
3. Filariasis
4. Typhoid

Answer: 4. Typhoid

Question 33. Which of the following snakes directly give birth to young ones?

1. Cobra
2. Krait
3. Viper
4. Chandra bora

Answer: 3. Viper

Question 34. Which fish guard their babies till the eggs hatch and grow into adults?

1. Rahu
2. Bhetki
3. Gojal
4. Pomphret

Answer: 3. Gojal

Question 35. The largest creatures on Earth are

1. Blue whales
2. Sperm whales
3. Elephants
4. Humpback whales.

Answer: 1. Blue whales

 

Chapter 11 Habits And Habitats Of Some Important Animals The Habits And Behaviour Of Some Animals Fill In The Blanks

Question 1. Ants are truly social or __________ insects.
Answer: Eusocial

Question 2. The queen ant emits a __________ that workers behave in the way they do.
Answer: Scent

Question 3. Termites are closely related to __________.
Answer: Cockroaches

Question 4. ________ termites undertake the most labour within the colony.
Answer: Worker

Question 5. Termites are __________ at any level of decomposition.
Answer: Detritivores

Question 6. Trophallaxis is found in __________.
Answer: Termites

Question 7. The scientific name of the Indian honey bee is __________ indicia.
Answer: Apis

Question 8. Honey bees live in a nest called __________.
Answer: Hive

Question 9. Most bees in a hive are __________.
Answer: Workers

Question 10. Male bees are produced by __________.
Answer: Parthenogenesis

Question 11. The African elephant is __________ africana.
Answer: Loxodonta

Question 12. Elephants are considered to be __________ species due to their impact on their environments.
Answer: Keystone

Question 13. Elephants can live up to __________ to years in the wild.
Answer: 70

Question 14. Wild chimpanzees are found exclusively in __________.
Answer: Africa

Question 15. __________ is the most important component of a chimpanzee’s diet.
Answer: Fruit

Question 16. Field studies of common chimpanzees were pioneered by primatologist __________.
Answer: Jane Goodall

Question 17. Chimpanzees make __________ and use them to acquire food.
Answer: Tools

Question 18. __________ birds fly hundreds and thousands of kilometres.
Answer: Migratory

Question 19. Birds can get compass information from the __________, the stars, and by sensing the earth’s magnetic field.
Answer: Sun

Question 20. __________ whales communicate with each other with the help of musical songs.
Answer: Humpback

Question 21. The genus __________ comprises crows, ravens and rooks.
Answer: Corvus

Question 22. Crows are __________ which means they eat nearly anything.
Answer: Omnivores

Question 23. The word __________ is derived from Spanish for “little fly”.
Answer: Mosquito

Question 24. Anopheles larvae lie __________ of the water.
Answer: Parallel

Question 25. All fish have __________ that allow them to breathe water.
Answer: Gills

Question 26. Male sea horses have __________ to receive fertilized eggs.
Answer: Brood pouches

Question 27. Snakes belong to the animal class __________.
Answer: Reptilia

Question 28. Living snakes are found on every continent except __________.
Answer: Antarctica

Question 29. The snake __________ is modified saliva, delivered through fangs.
Answer: Venom

Question 30. The tiger is the largest __________ species.
Answer: Cat

Question 31. To identify his territory, the male tiger marks trees by spraying __________
Answer: Urine

Question 32. Baleen whales have no __________
Answer: Teeth

Question 33. Whales have a layer of fat known as __________ under the skin.
Answer: Blubber

Question 34. Killer whales can live a maximum of __________ years.
Answer: 35

 

Chapter 11 Habits And Habitats Of Some Important Animals The Habits And Behaviour Of Some Animals Identify As True Or False

Question 1. Many scientists study animal behaviour because it sheds light on human beings.
Answer: True

Question 2. Ants are truly social or eusocial insects.
Answer: True

Question 3. Worker ants are males.
Answer: False

Question 4. Termites are a type of ant.
Answer: False

Question 5. Termite workers and soldiers are sterile.
Answer: True

Question 6. The process of worker termites feeding other nestmates is known are trophallaxis.
Answer: True

Question 7. The termite queen of the colony is responsible for egg production for the colony.
Answer: True

Question 8. Some species of termite practice agriculture.
Answer: False

Question 9. Termites have very hard cuticles.
Answer: False

Question 10. Apis India is an Indian honey bee.
Answer: True

Question 11. A single hive can have up to 80,000 bees, mostly males.
Answer: False

Question 12. A honeycomb is a layer of wax cells made into a hexagonal shape.
Answer: True

Question 13. Male Indian elephants are the largest extant terrestrial animals.
Answer: False

Question 14. Elephants are carnivorous animals.
Answer: False

Question 15. Chimpanzees are native to Africa.
Answer: True

Question 16. Fruit is the most important component of chimpanzees’ diet.
Answer: True

Question 17. Chimpanzees engage in apparently altruistic behaviour within groups.
Answer: True

Question 18. Birds migrate to move from areas of high or increasing resources to areas of low or decreasing resources.
Answer: False

Question 19. All black birds are crows.
Answer: False

Question 20. Crows are omnivores, which means they eat nearly anything.
Answer: True

Question 21. Many species of mosquitoes act as vectors of diseases.
Answer: True

Question 22. Aedes mosquitoes spread malaria.
Answer: False

Question 23. Stagnant water act as the breeding ground of mosquito.
Answer: True

Question 24. Fishes are mammals.
Answer: False

Question 25. All fish have gills that allow them to breathe water.
Answer: True

Question 26. Sea horses are fishes.
Answer: True

Question 27. Snakes are herbivorous.
Answer: False

Question 28. Snakes use smell to track their prey.
Answer: True

Question 29. Tigers are colonial animals.
Answer: False

Question 30. Tigers are good swimmers.
Answer: True

Question 31. The population of tigers has been estimated using plaster casts of their pugmarks.
Answer: True

Question 32. The tiger is an endangered species.
Answer: True

Question 33. Whales are large fishes.
Answer: False

Question 34. Whales have evolved from land-living mammals.
Answer: True

 

Chapter 11 Habits And Habitats Of Some Important Animals The Habits And Behaviour Of Some Animals Match The Columns

 

Answer: A-4, B-1, C-5, D-3

 

Answer: A-5,B-1,C-4,D-2

 

Answer: A-3, B-4, C-1, D-2

 

Chapter 11 Habits And Habitats Of Some Important Animals The Habits And Behaviour Of Some Animals Answer In Words Or A Sentence

Question 1. Give two examples of eusocial insects.
Answer: Ants and termites.

Question 2. How do ants communicate with each other?
Answer: Through tapping with the antennae and smell.

Question 3. What are white ants?
Answer: Termites are called white ants.

Question 4. Name the process of worker termites feeding other nest mates.
Answer: Trophallaxis.

Question 5. Which protozoan species is found in the gut of termites?
Answer: Trichonympha.

Question 6. Write the scientific name of the Indian honey bee.
Answer: Apis indica.

Question 7. What is a hive?
Answer: Nest of honey bees.

Question 8. What is the shape of a honeycomb?
Answer: Hexagonal.

Question 9. What is the scientific name of the African elephant?
Answer: Loxodonta africana

Question 10. Name a primatologist.
Answer: Jane Goodall.

Question 11. Name a non-human mammal capable of making tools.
Answer: Chimpanzees.

Question 12. Name a migratory bird found in Kolkata.
Answer: Brown Shrikes.

Question 13. What is the common name of Corvus spleens?
Answer: House crow.

Question 14. What is a raven?
Answer: A type of crow.

Question 15. Name the mouth part of a mosquito associated with biting.
Answer: Proboscis.

Question 16. Which mosquitoes spread yellow fever?
Answer: Aedes.

Question 17. Name a gill-breathing vertebrate.
Answer: Fish.

Question 18. Is a sea horse a mammal?
Answer: No, it is a fish.

Question 19. Do snakes respond to the sound of flutes?
Answer: No.

Question 20. Which snake directly gives birth to young?
Answer: Chandrabora.

Question 21. Which is the largest cat?
Answer: Tiger.

Question 22. Write the scientific name of the Royal Bengal Tiger.
Answer: Panthera tigris.

Question 23. Give an example of an endangered mammal.
Answer: Tiger.

Question 24. Name an aquatic mammal.
Answer: Whale.

Question 25. Name a fish which builds a nest in long furrows on the underwater soft floor of the earth.
Answer: Tilapia.

 

Chapter 11 Habits And Habitats Of Some Important Animals The Habits And Behaviour Of Some Animals Short Answer Type Questions

Question 1. What is trophallaxis?
Answer: The process of worker termites feeding other nest-mates is known as trophallaxis. Trophallaxis is an effective nutritional tactic to convert and recycle nitrogenous components.

Question 2. What is a detritivore?
Answer: It is an organism that feeds on dead decomposing organic matter. Example-
termite.

Question 3. What is a pheromone?
Answer: A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species.

Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behaviour of the receiving individual.

Question 4. What is eusociality?
Answer: Eusociality is a form of social organization. It is an extensively studied social system displayed by some insects like ants, bees, termites, etc.

Question 5. What is a bee hive?
Answer: A bee hive is an enclosed structure in which honey bee species live and raise their young.

Natural bee hives are naturally occurring structures occupied by honey bee colonies, such as hollowed-out trees, while domesticated honey bees live in man-made bee hives, often in an apiary.

Question 6. What is bee dance?
Answer: It is a pattern of movement exhibited by worker honey bees to communicate about the distance and direction of food sources. It is performed in the front of the hive to instruct fellow workers.

Question 7. What are keystone species?
Answer: A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance.

Such species are described as playing a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem. Example-elephant.

Question 8. What is bird migration?
Answer: Bird migration refers to the regular (and often seasonal) journeys to and from a given area undertaken by all or part of a bird population. Not all bird species are migratory.

Question 9. Write about the role of mosquitoes in spreading diseases.
Answer: Mosquitoes are known to carry many infectious diseases from several different classes of microorganisms, including viruses and parasites.

Mosquito-borne illnesses include malaria, elephantiasis, dengue fever, yellow fever, etc.

Question 10. What is mosquito control?
Answer: Mosquito control manages the population of mosquitoes to reduce their damage to human health, economies, and enjoyment.

Mosquito control is a vital public-health practice throughout the world and especially in the tropics because mosquitoes spread many diseases, such as malaria.

Question 11. What is a fish shoal?
Answer: Any group of fish that stays together for social reasons is said to be shoaling, and if the shoal is swimming in the same direction together, it is schooling.

Question 12. What is snake charming?
Answer: Snake charming is the practice of pretending to hypnotize a snake by playing an instrument called bansuri.

A typical performance may also include handling the snakes or performing other seemingly dangerous acts, as well as other street performance staples, like juggling and sleight of hand.

Question 13. What are baleen whales?
Answer: Baleen whales are some of the largest animals on Earth. Characteristic baleen plates and paired blowholes help distinguish baleen whales from toothed whales.

Question 14. Mention two differences between a common crow and a Raven.
Answer:

1.  A Raven is bigger in size than a common crow.
2.  Common crows have wings, tails, necks, heads and beaks jet black in colour but the nape (back of the neck) and belly are grey in colour. The entire body of the raven is jet-black in colour.

Question 15. Name four venomous snakes.
Answer: Cobra, Common Krait, Russell’s Viper and Banded Krait.

Question 16. What is the cause of migration for migratory birds?
Answer: Migratory birds fly to find the best ecological conditions and habitats for feeding, breeding and raising their young.

Birds migrate from areas of decreasing resources to areas of increasing or high resources. The two primary resources being sought are food and nesting locations.

Question 17. Why is the number of chimpanzees becoming less?
Answer: Due to the disturbance of the poachers and due to the decrease of the natural habitat (forest land), the number of chimpanzees is gradually decreasing.

Question 18. Which body systems are affected by snake venoms?
Answer: Some snake venoms affect the nervous system while some affect the blood circulatory system.

Question 19. The termites do not usually come out of their holes – Why?
Answer: Termites do not have a hard shell on them. So, if they are too exposed to sunlight, the water in their bodies dries up. That is the reason why they usually do not come out of their holes.

Question 20. What are the functions of blubber in a whale?
Answer: The functions of the blubber or the thick layer of fat under the skin are

1. It insulates the whale from a harsh and cold climate and helps to maintain the body temperature.
2. This provides energy for movement.
3. It also helps with buoyancy and protection from predators.

 

Chapter 11 Habits And Habitats Of Some Important Animals The Habits And Behaviour Of Some Animals Long Answer Type Questions

Question 1. Ants are not seen much during winter months – Why? How do red ants make black ants their slaves?
Answer: During winter months ants build nests under the earth and feed on stored food. Hence they are not seen much during winter.

Red ants are good at fighting. When they feel the urgency to store food, they start fighting with the black ants. As a consequence, the black ants are defeated and they die.

The red ants carry away the eggs from their nest in their mouths to their own nest. When the eggs hatch, these black ants that come out spend their entire life serving those red ants.

Question 2. Write about the behaviour of chimpanzees.
Answer:

Chimpanzees

Chimpanzees (sometimes called chimps) are one of two exclusively African species of great ape that are currently extant. Native to Sub- Saharan Africa, both are currently found in the Congo jungle.

Classified in the genus Pan, they were once considered to be one species.

However, since 1928, they have been recognized as two distinct species the common chimpanzee (Pan troglodytes) live in the north of the Congo River and the bonobo (Pan paniscus) which live in the south.

The most obvious differences are that chimpanzees are somewhat larger, more aggressive and male-dominated, while the bonobos are more gracile, peaceful, and female-dominated.

Their hair is typically black or brown. Males and females differ in size and appearance. Standing approximately 4 feet high, males weigh about 45-55 kg, while females weigh between 30-50 kg.

Both chimps and bonobos are some of the most social great apes, with social bonds occurring among individuals in large communities.

Fruit is the most important component of a chimpanzee’s diet; however, they will also eat vegetation, bark, honey, insects and even other chimps or monkeys.

Chimpanzees rarely live past the age of 50 in the wild but have been known to reach the age of 60 in captivity. Chimpanzees and bonobos are equally the closest living relatives.

As such, they are among the largest-brained, and most intelligent of primates; they use a variety of sophisticated tools and construct elaborate sleeping nests each night from branches and foliage.

They have both been extensively studied for their learning abilities.

There may even be distinctive cultures within populations. Field studies of common chimpanzees were pioneered by primatologist Jane Goodall.

Both Pan species are considered to be endangered as human activities have caused severe declines in the populations and ranges of both species.

Several conservation and rehabilitation organisations are dedicated to the survival of Pan species in the wild.

Anatomical differences between the common chimpanzee and the bonobo are slight, but sexual and social behaviours are markedly different.

The common chimpanzee has an omnivorous diet. Chimps occasionally hunt and eat meat. The bonobo, on the other hand, has a mostly frugivorous diet and non-violent, matriarchal behaviour.

Different groups of chimpanzees also have different cultural behaviour with preferences for types of tools.

The common chimpanzee tends to display greater aggression than the bonobo. The average, captive chimpanzee sleeps 9.7 hours a day.

Studies have shown chimpanzees engage in apparently altruistic behaviour within groups. Chimpanzees live in large multi-male and multi-female social groups, which are called communities.

Within a community, the position of an individual and the influence the individual has on others dictates a definite social hierarchy.

Chimpanzees live in a leaner hierarchy wherein more than one individual may be dominant enough to dominate other members of lower rank.

Typically, a dominant male is referred to as the alpha male. The alpha male is the highest-ranking male that controls the group and maintains order during disputes.

In chimpanzee society, the ‘dominant male’ sometimes is not the largest or strongest male but rather the most manipulative and political male that can influence the goings on within a group.

Male chimpanzees typically attain dominance by cultivating allies who will support that individual during future ambitions for power.

Lower-ranking chimpanzees will show respect by submissively gesturing in body language or reaching out their hands while grunting.

Female chimpanzees will show deference to the alpha male by presenting their hindquarters.

Chimps live in communities. These communities are composed of family groups of three to six individuals, totalling about 50 animals.

Most mothers give birth to one young an average of every five to six years in the wild. Young chimps stay with their mothers for up to 10 years.

Chimpanzees make tools and use them to acquire food and for social displays; they have sophisticated hunting strategies requiring cooperation, influence and rank; they are status.

Conscious, manipulative and capable of deception; they can learn to use symbols and understand aspects of human language including some relational syntax, concepts of numbers and numerical sequence; and they are capable of spontaneous planning for a future state or event.

Recent research indicates that chimpanzees’ use of stone tools dates back at least 4,300 years (about 2,300 BC).

One example of chimpanzee tool usage behaviour includes the use of a large stick as a tool to dig into termite mounds and the subsequent use of a small stick altered into a tool that is used to “fish” the termites out of the mound.

Chimpanzees are also known to use smaller stones as hammers and a large one as an anvil in order to break open nuts.

Question 3. What are the harmful effects of mosquitoes and how to control them?
Answer:

Mosquitoes

Mosquitoes are small insects. The word “mosquito” is derived from Spanish for “little fly”.

Thousands of species feed on the blood of various kinds of hosts, mainly vertebrates, including mammals, birds, reptiles, amphibians, and even some kinds of fish.

 

 

Both males and females feed mainly on fruit and plant nectar, but the female also needs the protein in her blood to help her eggs develop.

Once she’s had her fill of blood, she’ll rest for a couple of days before laying her eggs. The females “bite” with a long, pointed mouthpart called a proboscis.

They use the serrated proboscis to pierce the skin and locate a capillary, then draw blood through one of two tubes.

They also have a head, thorax and abdomen. On the head, there are two large compound eyes, two ocelli (simple eyes), two antennae and a proboscis.

Two large, scaled wings sprout from the thorax. twigs, hair, twine, bark, plant fibres, mosses, cloth and other materials.

Crows and ravens are important in mythology, fables and native cultures. They are often identified as clever tricksters.

In some cultures, they are symbols of good luck; in others, they bring bad luck. A group of crows is called a “murder”.

There are several different explanations for the origin of this term, mostly based on old folk tales and superstitions.

Many view the appearance of crows as an omen of death because ravens and crows are scavengers and are generally associated with dead bodies, battlefields, and cemeteries and they are thought to circle in large numbers above sites where animals or people are expected to die soon.

According to the International Union for Conservation of Nature (IUCN), most crows are not endangered.

Though the loss of blood is seldom of any importance to the victim, the saliva of the mosquito often causes an irritating rash that is a serious nuisance.

Much more serious though, are the roles of many species of mosquitoes as vectors of diseases.

In passing from host to host, some transmit extremely harmful infections such as malaria, yellow fever, Chikungunya, dengue fever, filariasis, Zika virus, etc. rendering it the deadliest animal family in the world.

Females can beat their wings up to 500 times per second, and the males pick out the higher frequency of those beats when seeking a mate.

Most mosquitoes can fly no more than about one to three miles and often stay within several hundred feet of where they were hatched.

They have receptors on their antennae that detect the carbon dioxide released when we exhale. Those plumes of CO, rise into the air, acting as trails that the mosquitoes follow to find the source.

Our skin produces several chemical odours, and some of them are like dinner to mosquitoes. There are more than 2,700 species of mosquitoes in the world. Of these genera, most mosquitoes belong to three

1. Aedes:

Aedes mosquitoes have abdomens with pointed tips. They include such species as the yellow-fever mosquito and the Asian tiger mosquito.

Adults of this mosquito have black bodies with conspicuous white stripes. They Coopersistently bite mammals (especially humans), mainly at dawn and in the early evening.

Their bites are painful. They b spread “Yellow fever”, Encephalitis, Si Dengue fever, etc.

 

 

2. Anopheles:

These tend to breed in bodies of permanent fresh water. Anopheles mosquitoes also have abdomens with no pointed tips.

They include several species, such as the common malaria mosquito that can spread malaria to humans.

3. Culex:

These tend to breed in quiet, standing water. Culex mosquitoes have an abdomen with blunt tips. They are weak fliers and tend to live for only a few weeks during the summer months.

They persistently bite (preferring birds over humans) and attack at dawn or after dusk. Their bite is painful. Culex causes filariasis, bird malaria, encephalitis, and dengue.

Sound is produced due to the flapping of the wings of mosquitoes. Smaller mosquitoes produce more sound.

Like all insects, mosquitoes hatch from eggs and go through several stages in their life cycle before becoming adults.

The female lay their eggs in water, and the larva and pupa stages live entirely in water. When the pupa change into adults, they leave the water and The adult mosquitoes become free-flying land insects.

Egg:

All mosquitoes lay eggs in water, which can include large bodies of water, standing water (like swimming pools) or areas of collected standing water (like tree holes or gutters).

Females lay their eggs on the surface of the water, except for Aedes mosquitoes, which lay their eggs above water in protected areas that eventually.

flood. The eggs can be laid singly or as a group that forms a floating raft of mosquito eggs.

 

 

Larva:

The mosquito eggs hatch into larvae or “wigglers”, which live at the surface of the water and breathe through an air tube or siphon.

As they grow, they shed their skin (moult) several times. Mosquito larvae can swim and dive down from the surface when disturbed.

Pupae:

After the fourth moult, mosquito larvae change into pupae, or “tumblers”, which live in the water anywhere from one to four days depending on the water temperature and species.

The pupae float at the surface and breathe through two small tubes (trumpets). At the end of the pupal stage, the pupae encase themselves and transform into adult mosquitoes.

Adult:

Inside the pupal case, the pupae transform into an adult.

The adult uses air pressure to break the pupal case open, crawls to a protected area and rests while its external skeleton hardens, spreading its wings out to dry. Once this is complete, it can fly away and live on the land.

Identifying larvae:

We can distinguish the larvae of various species of mosquito. Anopheles larvae lie parallel to the surface. of the water, while larvae of Aedes and Culex extend down into the water.

Mosquito Control Methods:

Insecticides can be used to help control mosquitoes. Some products are designed to be applied directly to water to control mosquito larvae, while others are used more broadly to control adult mosquitoes.

1. There are steps you can take to reduce mosquito populations without using insecticides. Here are some tips to consider when trying to avoid mosquito bites:
2. Empty water from containers such as flower pots, birdbaths, pet water dishes, cans, gutters, tires and buckets regularly to disrupt the mosquito breeding cycle.
3. Keep windows and door screens in good working order to prevent mosquitoes from entering your home.
4. If possible, wear long-sleeved shirts and long pants while outdoors, consider staying indoors early in the morning and evening when mosquitoes are most active. Consider using an insect repellent.

 

Question 4. Write about the parental care of fish.
Answer: A fish is an animal which lives and breathes in water. All fishes are vertebrates (have a backbone) and most breathe through gills and have scales.

Fish make up about half of all known vertebrate species. Fish have been on the earth for more than 500 million years.

 

 

Fish were well established long before dinosaurs roamed the earth. There are three classes of fish: jawless, cartilaginous, and bony.

Fish are cold blooded, which means their internal body temperature changes as the surrounding temperature changes. 40% of all fish species inhabit fresh water.

Some fish like sharks don’t possess an air bladder to help keep them afloat and must either swim continually or rest on the bottom.

Some species of fish can fly (glide), others can skip along the surface and others can even climb rock.

Fish have a specialized sense organ called the lateral line which works much like radar and helps them navigate in dark or murky water.

Fish have excellent senses of sight, touch, and taste and many possess a good sense of smell and ‘hearing’. Fish feel pain and suffer stress just like mammals and birds.

Fish eat other fish, fish eggs, molluscs, aquatic plants, algae, zooplankton, terrestrial insects, water birds, turtles, frogs, etc.

In some species the males and females have different shaped bodies or different colouring; in other species, there is no visible difference. A person who studies fish is called an ichthyologist.

All fish have gills that allow them to breathe underwater. Just like we use our lungs to exchange oxygen for carbon dioxide from the air, the gills of a fish perform a similar function to water.

So fish still need oxygen to live, they just get it from the water instead of the air. Fish live in nearly every large body of water in the world including streams, rivers, ponds, lakes, and oceans.

Some fish live on the surface of the water and some live in the very depths of the ocean. There are fish that live in fresh water and others that live in salt water.

The reproduction of a species has to assure the survival of the species. Spawning occurs when the moment is the best for the survival of the fry, abundant food, shelter etc.

After spawning occurs, the eggs may be left or abandoned, or there may be some degree of parental care provided for by the male and/or female.

Parental care is not the rule in fish. Most species are quite content to abandon their offspring to the vagaries of a world populated by organisms that are fond of eating nutritious little snakes such as eggs and fry.

Though they may form a minority, parental species are nevertheless very diverse. They belong to many different families, marine as well as freshwater.

About 80% of these families are represented by species that care only for eggs.

These fishes prepare or build nests, sometimes nothing more than a cleaned rock, sometimes an amalgamation of vegetal matter, empty shells, pebbles, sand, or even air bubbles.

 

 

Parents also tirelessly fan the eggs-moving water over the brood with movements of their fins to provide them with a good supply of oxygen.

In addition, they clean the eggs by brushing them with their fins. With their mouth, they remove dead or diseased eggs. Some transfer mucus onto their eggs which has anti-microbial properties.

If the nest is in the intertidal zone, parents cover the egg batch with algae just before low tide, preventing desiccation.

Many species carry eggs with them so that if a big predator makes an entry onto the scene, the parents can flee and bring the brood with them.

The eggs are carried outside or inside the body.

Examples of outside carriers include medakas (eggs stuck to the female’s vent for a few hours), bagrid and banjo catfishes (eggs embedded on the surface of the belly) and sucker-mouth armoured catfishes (eggs attached to the male’s lower lip).

Inside- carriers include the numerous species of mouth-brooding cichlids (Cichlids are popular freshwater fish kept in the home aquarium), sea catfishes, lumpfishes, cardinalfishes and gouramis (eggs carried inside the mouth, and regularly churned in there for proper cleaning and oxygenation), many seahorses and pipefishes (eggs developing inside a special ventral pouch on the male).

Seahorses are monogamous. The males incubate the eggs that are received from the female. Females do not play any parental care after mating.

Fertilization and incubation of oocytes received from females take place in a sac-like brood pouch located under the tail.

 

 

In most mouthbrooders (those species that carry eggs and fry within their mouth), only one parent provides care.

When all bony fishes are considered as a group, female-only care is the rarest form of parental involvement. The most common form is male-only care.

In such species, males aggressively stake out territories, prepare a spawning site, and court passing females.

Question 5. The nighttime vision of tigers is excellent – explain.
Answer: The Tiger (Panthera tigris) is the largest cat species, most recognisable for its pattern of dark vertical stripes on reddish-orange fur with a lighter underside.

Tigers have muscular bodies with powerful forelimbs, large heads and long tails.

The fur is dense and heavy; colouration varies between shades of orange and brown with white ventral areas and distinctive vertical black stripes, whose patterns are unique to each individual.

Their function is likely for camouflage in vegetation such as long grass with strong vertical patterns of light and shade.

They have a mane-like heavy growth of fur around the neck and jaws and long whiskers, especially in males. The pupils are circular with yellow irises.

The small, rounded ears have a prominent white spot on the back, surrounded by black.

A Tiger’s canine teeth can grow up to three inches long and are easily capable of crunching through the spine of any creature on Earth.

White tigers, this recessive colour variant is found only in the Bengal subspecies and with regular stripes and blue eyes. It is not albinism.

They appear on many flags, and coats of arms, and as mascots for sporting teams. The tiger is the national animal of India, Bangladesh, Vietnam, Malaysia and South Korea.

Adult tigers lead largely solitary lives. They establish and maintain territories but have much wider home ranges within which they roam.

Resident adults of either sex generally confine their movements to their home ranges, within which they satisfy their needs and those of their growing cubs.

Individuals sharing the same area are aware of each other’s movements and activities. The size of the home range mainly depends on prey abundance, and in the case of males, on access to females.

Tigers are strong swimmers and often deliberately bathe in ponds, lakes and rivers as a means of keeping cool in the heat of the day. They are able to carry prey through or capture it in the water.

To identify his territory, the male marks trees by spraying urine and anal gland secretions, as well as marking trails with faeces and marking to typically absent, they have been observed via remote-controlled hidden cameras.

They generally hunt alone and ambush their prey as most other cats do, overpowering them from any angle, using their body size and strength to knock the prey off balance.

After killing their prey, tigers sometimes drag it to conceal it in vegetative cover, usually pulling it by grasping with their mouths at the site of the killing bite.

This too, can require great physical strength. zieminA transom trees or the ground with their claws. Females also use these “scrapes”, as well as urine and scat markings.

Scent markings of this type allow an individual to pick up information on another’s identity, sex and reproductive status.

Roar is produced in a variety of situations such as taking down large prey, signalling sexual receptivity and females calling to their young. These roars may be heard from distances over 3 km.

Male tigers are generally more important to other males within their territories than females are of other females.

Territory disputes are usually solved by displays of intimidation rather than outright aggression.

 

 

In the wild, tigers mostly feed on large and medium-sized animals, preferring native ungulates weighing at least 90 kg. They typically have little or no deleterious effect on their prey populations.

Sambar deer, chital, barasingha, wild boar, gaur, nilgai and both water buffalo and domestic buffalo, etc. are the tiger’s favoured prey in India.

They also prey on other predators, including dogs, leopards, pythons, sloth bears and crocodiles.

Tigers generally do not prey on fully grown adult Asian elephants and Indian rhinoceros but incidents have been reported.

Old or wounded tigers, unable to catch wild prey, can become man-eaters; this pattern has recurred frequently across India.

An exception is in the Sundarbans, where healthy tigers prey upon fishermen and villagers in search of forest produce, humans thereby forming a minor part of the tiger’s diet.

Tigers are thought to be mainly nocturnal predators, but in areas where humans are Tigers make extensive use of their vision for everyday functions and applications (in much the same way as human beings), particularly for hunting during the darkness of night or the limited visibility of dusk or storms.

Tigers hunt mainly during the evening and night times when the vision of their prey is compromised. For this reason, their nighttime vision is excellent; about six times better than that of humans.

There are several adaptations within the actual eye that allow for this. It has a wide, rounded pupil that allows maximum light to enter into the eye, when necessary.

The tiger’s retinas comprise mainly rod receptors, which are cells that are sensitive to low light levels and can perceive very slight movements.

There are some cone cells (colour receptors) in each eye, but these are used more for day vision, and not to perceive a range of different colours.

In fact, it is thought that some tigers only see dull greens, blues and reds, while others see in black and white.

The tapetum lucidum is a layered, mirror-like structure behind the retina that reflects light back into the eyes for a second time so that the eye and brain can form a brighter image of it.

The eyes of the tiger are situated on the front of its head, and not on the sides. This helps with three-dimensional perception and depth perception since both eyes look ahead.

Mating can occur all year round but is more common between November and April. A female is only receptive for three to six days. Mating is frequent and noisy during that time.

The litter is usually two or three cubs, occasionally as few as one or as many as six. Cubs are born blind and helpless.

The females rear them alone, with the birth site and maternal den in a sheltered location such as a thicket, cave or rocky crevice. The male generally takes no part in rearing them.

First tigress hunts and gives pieces of meat to the cubs. The tigers teach them to eat the meat by showing them how to tear it with their teeth.

She also teaches them to swim. After training from the mother for six or seven months, the tigers finally become adults.

The tiger is an endangered species. Poaching for fur and body parts and the destruction of habitat have simultaneously greatly reduced tiger populations in the wild.

At the start of the 20th century, it is estimated there were over 100,000 tigers in the wild, but the population has dwindled outside of captivity to between 1,500 and 3,500.

India is home to the world’s largest population of wild tigers. In 1973, India’s Project Tiger established over 25 tiger reserves in reclaimed land, where human development was forbidden.

Tigers occupy a variety of habitats from tropical forests, evergreen forests, woodlands and mangrove swamps to grasslands, savannah and rocky country.

Tigers do not actually live in Africa; they live in Asia. Tigers are seated at the top of the food chain predators maintaining the ecological balance of populations by keeping prey populations in check.

When a tiger has eaten its prey, the abandoned prey becomes the food for a variety of mammals, birds and reptiles.

Some cultures believe that powdered tiger bones have medicinal value. Unfortunately, tigers are highly in demand to supply this damaging market.

Question 6. Write about the rules of elephant society.
Answer:

Elephants

Elephants are large mammals. Two species are traditionally recognised, the African elephant (Loxodonta africana) and the Asian elephant (Elephas maximus).

Male African elephants are the largest extant terrestrial animals and can reach a height of 4 m (13 ft) and weigh 7,000 kg.

All elephants have several distinctive features, the most notable of which is a long trunk or proboscis, used for many purposes, particularly breathing, lifting water and grasping objects.

Their incisors grow into tusks, which can serve as weapons and as tools for moving objects and digging. Elephants’ large ear flaps help to control their body temperature.

Their pillar-like legs can carry their great weight. African elephants have larger ears and concave backs while Asian elephants have smaller ears and convex or level backs.

As they are huge in size, elephants eat a lot. Each elephant can eat up to one hundred and fifty kg of grass-branches leaves in a day.

Elephants are herbivorous and can be found in different habitats including savannahs, forests, deserts and marshes. They prefer to stay near water.

They are considered to be keystone species due to their impact on their environments.

Other animals tend to keep their distance whereas predators such as lions, tigers, hyenas, and wild dogs usually target only young elephants.

Females tend to live in family groups, which consist of one female with her calves or several related females with offspring.

The groups are led by an individual known as the matriarch, often the oldest female. Males leave their family groups when they reach puberty (between the ages of 12-15), and may live alone or with other males.

Adult males mostly interact with family groups when looking for a mate and enter a state of aggression known as musth, which helps them gain dominance and reproductive success.

Calves are the centre of attention in their family groups and rely on their mothers for as long as three years. The rules in an elephant society are rather strict.

If an elephant calf gets lost while walking in the forest, the herd tries to search it out. But if they see that the lost calf has found a human shelter, they never accept it back.

Elephants can live up to 70 years in the wild. They communicate by touch, sight, smell and sound; elephants use infrasound, and seismic communication over long distances.

Elephant intelligence has been compared with that of primates and cetaceans. They appear to have self-awareness and show empathy for dying or dead individuals of their kind.

Elephants are not territorial. The home range is between 10-70 km and possibly larger, depending on herd size and seasonality.

Elephants sleep about approximately four hours a night. Elephants are crepuscular in nature, primarily active at dawn and dusk (twilight hours) when the environment is cooler.

Question 7. What is the trunk of an elephant made of? What are its functions?
Answer: The trunk or proboscis of an elephant is formed by the joining of the nose with the upper lip.

The trunk is used to smell the air, to break branches of trees, to suck and pour water into the mouth and to uproot grass from the ground and to put it in the mouth. It is also used to grasp any other object in the elephant’s way.

Question 8. How is a tiger’s body adapted to catch its prey?
Answer: A tiger’s body is superbly adapted for predation.

1. They have extremely strong jaws with sharp and long canine teeth for crunching.
2. The long retractable claws help to grab and hold the prey.
3. Longer back legs help in jumping and a massive, muscular body is perfectly suitable to easily hunt animals even bigger than its own size.
4. They have very sharp vision and hearing senses. The Tapetum Lucidum of the retina helps it to see six times better than humans in the dark.
5.  The eyes allow better depth perception when hunting and body stripes make it harder for prey to see the tiger.

 

Chapter 10 Biodiversity And Its Classification Review Questions Environment Review Questions MCQs

Question 1. Five kingdom classification was introduced by

1. Darwin
2. Hutchinson
3. Lamarck
4. Whitaker

Answer: 4. Whitaker

Question 2. The bacteria that can utilize methane usually belong to

1. Archea
2. Mycoplasma
3. Eubacteria
4. Actinomycetes

Answer: 1. Archea

Read And Learn More: WBBSE Solutions For Class 6 School Science

Question 3. The following group of organisms is without flagella

1. Eubacteria
2. Protozoa
3. Fungi
4. Cyanobacteria

Answer: 4. Cyanobacteria

Question 4. The free-living nitrogen-fixing bacterial include

1. Rhizobium
2. Nostoc
3. Clostridium
4. Frankia

Answer: 3. Clostridium

Question 5. The organism that is in between virus and monera is

1. Chlamydia
2. Mycoplasma
3. Actinomycetes
4. Fungi

Answer: 1. Chlamydia

Question 6. The group having unicellular eukaryotes is

1. Monera
2. Protista
3. Fungi
4. Plantae

Answer: 2. Protista

Question 7. The group that is intermediate between

1. Mycoplasma
2. Cyanobacteria
3. Chlamydia
4. Actinomycetes

Answer: 4. Actinomycetes

Question 8. The diatoms have the following character

1. Valves
2. Silica wall
3. Both
4. Cilia

Answer: 3. Both

Question 9. Red tide is caused by

1. Diatoms
2. Dinoflagellates
3. Protozoa
4. Red algae

Answer: 2. Dinoflagellates

Question 10. Yeast belongs to

1. Zygomycetes
2. Oomycetes
3. Ascomycetes
4. Basidiomycetes.

Answer: 3. Ascomycetes

Question 11. Sexual reproduction is not found in

1. Ascomycetes
2. Oomycetes
3. Basidiomycetes
4. Deuteromycetes

Answer: 4. Deuteromycetes

Question 12. The amphibious plant is

1. Algae
2. Bryophyte
3. Pteridophyte
4. Gymnosperm

Answer: 2. Bryophyte

Question 13. The most developed gymnosperm is

1. Cycas
2. Pinus
3. Ginkgo
4. Gnetum

Answer: 4. Gnetum

Question 14. The naked-seeded plant is

1. Pinus
2. Riccia
3. Ferns
4. Chinarose

Answer: 1. Pinus

Question 15. The algae with xanthophyll belong to

1. Green algae
2. Yellow-green algae
3. Brown algae
4. Red algae

Answer: 2. Yellow-green algae

Question 16. The plant which belongs to vascular cryptogam is

1. Algae
2. Mosses
3. Ferns
4. Gymnosperm

Answer: 3. Ferns

Question 17. The animal with a flat body is

1. Flatworms
2. Roundworms
3. Annelida
4. Mollusca

Answer: 1. Flatworms

Question 18. The animal with a water vascular system is

1. Snail
2. Starfish
3. Cockroach
4. Earthworm

Answer: 2. Starfish

Question 19. The shark is

1. Bony fish
2. Cartilaginous fish
3. Lungfish
4. Amphibia

Answer: 2. Cartilaginous fish

Question 20. Platypus is a

1. Hemichordate
2. Cephalochordate
3. Urochordate
4. Vertebrate

Answer: 4. Vertebrate

Question 21. ‘Water Silk’ belongs to

1. Bryophyta
2. Algae
3. Pteridophyta
4. Fungi

Answer: 2. Algae

Question 22. Which among the following does not possess the notochord?

1. Vertebrata
2. Cephalochordata
3. Urochordata
4. Hemichordata

Answer: 4. Hemichordata

Question 23. The vertebrate which is terrestrial throughout life, which lays eggs on land and moves around with the help of abdominal scales is

1. Pisces
2. Amphibians
3. Reptiles
4. Birds

Answer: 3. Reptiles

Chapter 10 Biodiversity And Its Classification Fill in the Blanks

Question 1. The bacteria belongs to ___________.
Answer: Monera

Question 2. Methanogen belongs to ___________.
Answer: Archea

Question 3. The cyanobacteria are ___________ in color.
Answer: Blue-green

Question 4. Yeast belongs to ___________.
Answer: Ascomycetes

Question 5. Amphioxus belongs to ___________.
Answer: Cephalochordata

Question 6. Balanoglossus belongs to ___________.
Answer: Hemichordata

Question 7. ___________ are amphibious plants.
Answer: Bryophytes

Question 8. ___________ root is present in Cycas.
Answer: Corallid

Question 9. Chondricthyes belong to ___________ fish.
Answer: Cartilaginous

Question 10. The frog has fish ___________ chambered heart.
Answer: Three

Question 11. The unicellular animal is ___________.
Answer: Protozoa

Question 12. The largest animal group is ___________.
Answer: Arthropoda

Question 13. The flowering plants are called ___________
Answer: ASngiosperms

Question 14. The external pinna is a character of ___________
Answer: Mammals

Question 15. The reproductive structure of the fern is called ___________
Answer: Sorus

Question 16. The fungus without sexual reproduction is ___________.
Answer: Deuteroycetes

Question 17. The locomotory organ of algae is ___________.
Answer: Flagella

Question 18. The oomycetes produce the reproductive spore called ___________.
Answer: Oospore

Question 19. Retrogressive evolution is observed in ___________.
Answer: Urochordata

Question 20. Red tide is brought about by ___________.
Answer: Dinoflagellates

 

Chapter 10 Biodiversity And Its Classification Identify As True Or False

Question 1. Archebacteria can survive in extreme environmental conditions.
Answer: True

Question 2. Bacteria belong to the kingdom Protista.
Answer: False

Question 3. Mycoplasma is devoid of cell walls.
Answer: True

Question 4. The diatom cell wall is made of calcium.
Answer: False

Question 5. Riccia is a leafy bryophyte.
Answer: False

Question 6. Pteridophytes are vascular cryptogams.
Answer: True

Question 7. Gnetum is the most advanced gymnosperm.
Answer: True

Question 8. Angiosperms are subdivided into 3 major groups.
Answer: False

Question 9. Protozoa belong to the group of Protista.
Answer: True

Question 10. Fungi are non-chlorophyllous organisms.
Answer: True

Question 11. Zygospore is observed in Oomycetes.
Answer: False

Question 12. Hydra belongs to Ctenophora.
Answer: False

Question 13. Frogs belong to a group of amphibious organisms.
Answer: True

Question 14. Earthworm exhibits open circulation.
Answer: False

Question 15. Cephalochordata has notochord extended up to the head region.
Answer: True

Question 16. Insects belong to the group Arthropoda.
Answer: True

Question 17. Sponges do not have any structural organization.
Answer: True

Question 18. Tapeworms are bisexual animals.
Answer: True

Question 19. Hair is a characteristic feature of Amphibia.
Answer: False

Question 20. Mammals have external ears.
Answer: True

 

Chapter 10 Biodiversity And Its Classification Match The Columns

Answer: A-D, B-C, C-E, D-A

 

Answer: A-D, B-A, C-E, D-B

 

Answer: A-D, B-C, C-B, D-A

 

Answer: A-E, B-A, C-B, D-D

 

Answer: A-C, B-D, C-E, D-A

 

Chapter 10 Biodiversity And Its Classification Answer In Words Or A Sentence

Question 1. Name the component of the cell wall of bacteria.
Answer: Peptidoglycan.

Question 2. What is the color of cyanobacteria?
Answer: Blue-green.

Question 3. What is meant by PPLO?
Answer: Pleuro Pneumonia Like Organisms.

Question 4. What are the five major kingdoms?
Answer: Monera, Protista, fungi, Plantae, Animalia.

Question 5. What are the different types of diatoms?
Answer: Centric and Pinnate.

Question 6. What are the different types of bryophytes?
Answer: Hepaticae, anthracene, moss.

Question 7. Why bryophytes are called amphibious plants?
Answer: The bryophytes are called amphibious plants because they grow on land but reproduce with the help of water.

Question 8. Why pteridophytes are called vascular cryptogams?
Answer: They are lower plants with true xylem and phloem.

Question 9. Why is Gnetum advanced?
Answer: They have true xylem vessels and perianth.

Question 10. What are the two layers of tissue in Hydra?
Answer: Ectoderm and Endoderm.

Question 11. How can you identify monocot and dicot plants by their leaves?
Answer: Leaves of monocot plants have parallel venation while those of dicot plants have reticulate venation.

Question 12. Why are arthropods so-called?
Answer: They have jointed appendages.

Question 13. Why is Chordata so-called?
Answer: They are so-called because of the presence of notochord.

Question 14. Name the group under invertebrate chordate.
Answer: Urochordata and Cephalochordata.

Question 15. Write one difference between Gymnosperms and Angiosperms.
Answer: Gymnosperms do not bear fruits and the seeds remain exposed. Angiosperms bear fruits inside which seeds remain enclosed.

 

Chapter 10 Biodiversity And Its Classification Short Answer Type Questions

Question 1. Why are prokaryotes so-called?
Answer: The prokaryotes are without true nuclear membranes.

Question 2. What are the two types of bacteria?
Answer: The bacteria that retain Gram stain are called Gram-positive and the one which does not retain Gram stain are called Gram-negative.

Question 3. What are the major pigments present in cyanobacteria?
Answer: The blue-green c-phycocyanin, red-colored c-phycoerythrin, and chlorophyll-a.

Question 4. Why is Protista a mixed group?
Answer: The protista is a mixed group because it has all the unicellular eukaryotes including plant, animal, and fungal members.

Question 5. Why are myxomycetes close to protozoa?
Answer: These organisms have pseudopodia or false feet.

Question 6. What is a zygospore?
Answer: Zygospore is a thick-walled spore produced by the union of 2 gametangia, which act as resting spores and germinate to produce new plant bodies.

Question 7. What is meant by basidiospore?
Answer: It is the sexual reproductive spore found in basidiomycetes fungi. It is borne on an oval structure called basidia, on finger-like projections called sterigmata.

Question 8. What is Hepaticae?
Answer: It is a thalloid structure with an apical notch, growing in a round tier-like configuration, the individual thallus looks like a liver and that is why the name Hepaticae is given, for example, Riccia.

Question 9. What is meant by ferns?
Answer: They represent the advanced group of pteridophytes, having compound leaves, soft rhizomatous stems, and root-like rhizoids. The reproductive structure is borne on the ventral surface of the leaves and they are called sorus.

Question 10. What are coralloid roots?
Answer: The root of Cycas gets coiled after getting infected with cyanobacteria or blue-green algae, it helps in better absorption of nutrients.

Question 11. How male and female cones of Pinus can be identified?
Answer: The male cones are borne in the upper branches, they are small non-woody, and borne in clusters, while the female cones are borne in the lower branches, they are large, woody, 2- 3 arising from each branch.

Question 12. What is the reproductive structure of Angiosperms?
Answer: The reproductive structure of the angiosperm is called a flower. It consists of 4 whorls, 2 accessory whorls in the form of calyx and corolla, and 2 essential whorls, the male androecium and female gynoecium.

Question 13. What is metagenesis?
Answer: Metagenesis is the unique alternation of generation observed in cnidaria; the asexual reproductive stage is called a polyp, while the sexual reproductive stage is called medusae.

Question 14. Why tapeworms are an ideal parasite?
Answer: The tapeworms have a dorsoventrally flattened body, they have hooks and suckers for attachment, they absorb all along their body, they can regenerate their body, and they have multiple larval stages.

Question 15. What is the venous heart?
Answer: The heart of fish is a 2-chambered heart, so deoxygenated venous blood always flows through it, hence it is called a venous heart.

Question 16. How birds are adapted to fly?
Answer: The birds have a boat-shaped body, the anterior pair of limbs is modified to produce wings supported by long feathers, and the bones are made light because of the presence of air spaces within.

Question 17. How many cotyledons are present in the following plants
Answer: Betel nut, Pea, Cardamom, Pumpkin
Hence identify them as monocotyledonous or
dicotyledonous.
Monocotyledonous (seeds containing one cotyledon): Betel nut, Cardamom Dicotyledonous (seeds containing two cotyledons): Pea, Pumpkin

Question 18. List out two features that are not found in starfish but are present in rohu fish.
Answer:

Two features:

1. Presence of vertebral column.
2. Presence of bony endoskeleton.

Question 19. List out two major differences between vertebrates and invertebrates.
Answer:

Question 20. List two major differences between algae and fungi.
Answer:

Chapter 10 Biodiversity And Its Classification Long Answer Type Questions

Question 1. What are the major characteristics of cyanobacteria?
Answer:

Archebacteria:

1. They are the oldest organisms in this world.
2. They survive in extreme environmental conditions.
3. They are anaerobic and are the ancestor of present-day organisms, for example, Methanogenic bacteria.

Eubacteria:

1. These bacteria represent the largest group of prokaryotic organisms.
2. They are classified on the basis of cell wall structure example Gram positive and Gram negative in nature.
3. They are both aerobic and anaerobic in nature and can also be classified on the basis of nutrition, the presence or absence of flagella, for example, Mycobacterium, and Vibrio.

 

 

Cyanobacteria:

1. They are blue-green in color due to the stun presence of unique pigments called chlorophyll-a and c-phycocyanin.
2. They are without flagella, grow in water, and do not have true sexual reproduction.
3. They have nitrogen-fixing ability and may be used as biofertilizers, for example Nostoc, and Anabaena.

 

 

Mycoplasma :

1. They are bacteria-like organisms without any cell wall and so they are capable of slime changing their shape, also called Pleuronsdm Pneumonia Like Organisms (PPLO), for example, Mycoplasma.

 

 

Chlamydia:

1. This organism is an intermediate between viruses and living organisms.
2. It does not have true cells and causes parrot fever, for example, Chlamydia.

Actinomycetes:

1. They are intermediate between fungi and bacteria.
2. They are filamentous in nature and cut off thin-walled spores in chains.
3. They are mostly soil-borne, and produce yes, antibiotics, for example, Streptomyces.

Question 2. What are the structural peculiarities of PPLO?
Answer:

Monera

1. The unicellular prokaryotic organisms. which do not have true nuclei bound by a nuclear membrane.
2. These organisms are the oldest organisms in this world.
3. They can survive in extreme environmental conditions. Monera includes the following organisms.

Archebacteria:

1. They are the oldest organisms in this world.
2. They survive in extreme environmental conditions.
3. They are anaerobic and are the ancestor of present-day organisms, for example, Methanogenic bacteria.

 

Eubacteria:

1. These bacteria represent the largest group of prokaryotic organisms.
2. They are classified on the basis of cell wall structure example Gram positive and Gram negative in nature.
3. They are both aerobic and anaerobic in nature and can also be classified on the basis of nutrition, the presence or absence of flagella, for example, Mycobacterium, and Vibrio.

 

 

Cyanobacteria:

1. They are blue-green in color due to the stun presence of unique pigments called chlorophyll-a and c-phycocyanin.
2. They are without flagella, grow in water, and do not have true sexual reproduction.
3. They have nitrogen-fixing ability and may be used as biofertilizers, for example Nostoc, and Anabaena.

 

 

Mycoplasma :

1. They are bacteria-like organisms without any cell wall and so they are capable of slime changing their shape, also called Pleuronsdm Pneumonia Like Organisms (PPLO), for example, Mycoplasma.

 

 

Chlamydia:

1. This organism is an intermediate between viruses and living organisms.
2. It does not have true cells and causes parrot fever, for example, Chlamydia.

 

 

Actinomycetes:

1. They are intermediate between fungi and bacteria.
2. They are filamentous in nature and cut off thin-walled spores in chains.
3. They are mostly soil-borne, and produce yes, antibiotics, for example, Streptomyces.

Question 3. What is the intermediate between bacteria and fungi? State its structural features.
Answer:

Monera

1. The unicellular prokaryotic organisms. which do not have true nuclei bound by a nuclear membrane.
2. These organisms are the oldest organisms in this world.
3. They can survive in extreme environmental conditions. Monera includes the following organisms.

Archebacteria:

1. They are the oldest organisms in this world.
2. They survive in extreme environmental conditions.
3. They are anaerobic and are the ancestor of present-day organisms, for example, Methanogenic bacteria.

 

Eubacteria:

1. These bacteria represent the largest group of prokaryotic organisms.
2. They are classified on the basis of cell wall structure example Gram positive and Gram negative in nature.
3. They are both aerobic and anaerobic in nature and can also be classified on the basis of nutrition, the presence or absence of flagella, for example, Mycobacterium, and Vibrio.

 

Cyanobacteria:

1. They are blue-green in color due to the stun presence of unique pigments called chlorophyll-a and c-phycocyanin.
2. They are without flagella, grow in water, and do not have true sexual reproduction.
3. They have nitrogen-fixing ability and may be used as biofertilizers, for example Nostoc, and Anabaena.

 

Mycoplasma :

1. They are bacteria-like organisms without any cell wall and so they are capable of slime changing their shape, also called Pleuronsdm Pneumonia Like Organisms (PPLO), for example, Mycoplasma.

 

Chlamydia:

1. This organism is an intermediate between viruses and living organisms.
2. It does not have true cells and causes parrot fever, for example, Chlamydia.

 

Actinomycetes:

1. They are intermediate between fungi and bacteria.
2. They are filamentous in nature and cut off thin-walled spores in chains.
3. They are mostly soil-borne, and produce yes, antibiotics, for example, Streptomyces.

Question 4. Why are protozoa important? State its features.
Answer:

Protista

This group of organisms includes unicellular eukaryotes. It may include plants, animals, and fungi. It is a mixed group and includes the following organisms:

Unicellular green algae :

1. The unicellular green algae has a cellular wall and chloroplast and food remains stored in the pyrenoid.
2. They may be with or without flagella, for example, Chlamydomonas.

Diatoms:

1. They are unicellular algae, having two mo valves formed of silica.
2. They may be round or spindle-shaped, for example, Pennularia.

 

Myxomycetes:

1. They are intermediate between fungi and protozoa.
2. They have thread-like multi-nucleate structures and may be saprophytic or parasitic in nature, e.g. Plasmodiophora.

Dinoflagellates:

1. They are unicellular, formed of 2 valves with a central groove, and the two flagella are arranged in such a way that they are oriented at right angles.
2. They cause red tide in the sea, for example, Dinoclonium.

Protozoa :

1. They are unicellular organisms similar to animal cells, having cell membranes, and moving with the help of cilia or pseudopodia.
2. They may be saprophytic or parasitic in nature, for example, Entamoeba, and Paramoecium.

Question 5. What are the features of Conifer?
Answer:

Gymnosperms

These plants are big woody trees that usually bear cones containing naked seeds. They include the following:

Cycas :

1. The plant looks like a dwarf coconut tree, with a monopodial stem and apical crown of leaves.
2. The roots are coralloid in nature heavily infected with blue-green algae, for example, Cycas.

Conifer :

1. The trees are very large, the stem is woody, the leaves are spiny in nature, roots are infected with vesicular-arbuscular mycorrhizae, for example, Pinus.

Ginkgo:

The plants are endemic to Korea and Japan, small and shrub-like, with male cones and female megasporophyll having a pair of ovules, for example, Ginkgo.

Gnetum:

1. The plant is a small tree.
2. It is the most developed gymnosperm, having large leaves, male and female. reproductive cupules containing stamens and ovules protected by perianth.
3. They are considered intermediate. between gymnosperm and angiosperm, for example, Gnetum.

Question 6. Why is moss considered a higher plant?
Answer:

Bryophytes

These plants are intermediate between terrestrial and aquatic conditions and that is why they are called amphibious plants.

Hepatics:

1. These plants are thalloid in nature, growing along the surface of the soil.
2. They are differentiated into basal storage zone and upper photosynthetic zone.
3. They reproduce in the presence of water.
4. They are so-called because the plant body looks like a liver, for example, Riccia).

Anthocerotae :

1. These plants are intermediate between sad villa thalloid and leafy structures.
2. The plant body has a multi-tier and long horn-shaped spore-bearing structure called a capsule and so these plants are also called hornworts, for example, Anthoceros.

Moss :

1. These plants are leafy bryophytes.
2.  They have well-differentiated root, stem, and leaves and a well-differentiated spore-bearing structure called a capsule.
3. The spores have a specific mechanism of dispersal, for example, Pogonatum.

Question 7. Distinguish between monocot and dicot.
Answer:

Angiosperms

1. They are flowering plants mainly divided into two major groups, Monocotyledonae having a single cotyledon and Dicotyledonae having 2 cotyledons.
2. These plants are the largest at present in the world.

Monocotyledonous plants:

1. These plants have mostly non-woody stems, sheathing leaf bases, parallel venation, and trimerous flowers.
2. Single cotyledon in the seed.
3. Seeds with endosperm, for example, Paddy

Dicotyledonous plants: These plants have:

1. Woody stem with massive secondary unglad n wood.
2. Distinct stalked leaves with reticulate venation.
3. Pentamerous flowers.
4. Seeds non-endospermic.
5. Seeds with two cotyledons example Mango, Bengal gram.

 

 

Leaf venation:

Leaf venation is the arrangement pattern of the veins on the leaf blade. Leaf venation is basically of two types.

1. Reticulate venation:

1. In this type, the veins branch and unite forming a complicated network. All the veins are interconnected, like the strands of the net. Leaves of Dicot plants generally have reticulate venation, e.g. Hibiscus.

2. Parallel venation:

In this type, the veins run parallel or nearly parallel to each other and are connected by smaller veins. Leaves of Monocot plants generally have parallel venation, for example, banana, and wheat.

On the basis of nature and the size of stems, plants may be classified as Herbs, Shrubs, and Trees.

Herbs:

1. The plants are short with almost no branches and soft stems.
2. They are either creepers or climbers.
3. They are short in height. e.g. marigold.

Shrubs :

1. The plants are woody but not too tall and have many branches and leaves.
2. They look like bushes.
3. They are of medium height, for example, china rose.

Trees:

1. The plants are tall with strong stems.
2. They have many branches and leaves, for example, mango.

Question 8. What are groups of protostomes? State their features.
Answer:

Animalia

The animal kingdom is very large with different multicellular organisms. Before going into classification, let us define and understand some terms connected with it.

1. Metazoa :

A group that comprises all animals having the body composed of cells differentiated into tissues and organs.

2. Eumetazoa :

It comprises all major animal groups except sponges and has truly organized tissues.

3. Acoelomata:

Animals have no coelom or body cavity.

4. Pseudocoelomata:

Animals have no true coelom but have a cavity in between the cuticle and visceral organs filled up with fluid.

5. Coelomata:

Animals have true coelom or body cavities lying in between the body wall and the alimentary canal.

6. Diploblastica:

Animals whose body is formed of ectoderm and endoderm cells only.

7. Triploblastica:

Animals whose body is formed of ectoderm, mesoderm, and endoderm cells.

These groups are discussed below:

 

 

1. Invertebrate :

1. The animal has 2 layers.

Sponge:

1. The animal is without the definite organization of tissues.
2. They are sedentary in nature.
3. The body is formed of a calcareous shell having multiple pores called ostia and an apical pore called osculum, for example, Sycon assumes.

Cnidaria:

1. The animal is cylindrical in nature.
2. It has two layers, ectoderm, and endoderm.
3. The mouth is guarded by tentacles.
4. They exhibit extracellular and intracellular digestion.
5. The body consists of nematocysts, used for traping pray, for example, Hydra

 

 

Ctenophora:

1. The animal has 2 layers.
2. It is marine.
3. It has a locomotory organ in the form of comb plates and specialized cells for trapping prey called Suzaid business caul oblast cells, for example, Beroe.

Platyhelminthes :

1. The animal has a flattened body, the body is segmented.
2. The animal is bisexual showing self-autumn fertilization, and survives as an endoparasite, for example, cedes to Taenia.

 

 

Aschelminthes :

1. The animal is unisexual, having a pseudocolor.
2. The female is larger than the male.
3. They have a thick cuticle and survive as endoparasite, for example, Ascaris

 

 

Annelida :

1. The animal is cylindrical in nature, with metameric segmentation.
2. The animal may have red pigment haemoglobin but it is in the plasma.
3. The blood circulation is closed.
4. The animal is bisexual but is not capable of showing self-fertilization, for example, Pheretima posthuma (earthworm)

 

 

Arthropoda :

1. This animal group is the largest having 4 sub-groups.
2. They have open circulation with multi-chambered) sm heart.
3. The sexes are different and fertilization is internal, example Periplaneta americana (cockroach)

 

 

Mollusca:

1. The animal has a soft body covered by the mantle and well protected calcareous shell.
2. The sexes are different and are intermediate between open and closed circulation, for example, Pila

 

 

Echinodermata:

1. The animal has a calcareous endoskeleton with projections.
2. They have blood circulation and a water vascular system.
3. They are marine and feed from the sea bed i.e. benthonic inhabit, for example, Asterias (Starfish).

Hemichordata:

The animal is not under chordates, because they do not have notochord in the matured stage, e.g. Balanoglossus.

Urochordate:

1. The notochord (an elastic rod-like structure situated immediately above the alimentary canal and covered by a sheath.) is limited to the tail region.
2. The animal retains larval character in the adult stage and this phenomenon is called retrogressive metamorphosis example Ascidia

Cephalochordata:

1. The animal has a notochord extended up to the head region.
2. The animal has a tail fin and many characteristics as fish, for example, Amphioxus.

 

 

Question 9. What are chordates? Mention its characters.
Answer:

Animalia

The animal kingdom is very large with different multicellular organisms. Before going into classification, let us define and understand some terms connected with it.

1. Metazoa :

A group that comprises all animals having the body composed of cells differentiated into tissues and organs.

2. Eumetazoa :

It comprises all major animal groups except sponges and has truly organized tissues.

3. Acoelomata:

Animals have no coelom or body cavity.

4. Pseudocoelomata:

Animals have no true coelom but have a cavity in between the cuticle and visceral organs filled up with fluid.

5. Coelomata:

Animals have true coelom or body cavities lying in between the body wall and the alimentary canal.

6. Diploblastica:

Animals whose body is formed of ectoderm and endoderm cells only.

7. Triploblastica:

Animals whose body is formed of ectoderm, mesoderm, and endoderm cells.

These groups are discussed below:

 

 

1. Invertebrate :

1. The animal has 2 layers.

Sponge:

1. The animal is without the definite organization of tissues.
2. They are sedentary in nature.
3. The body is formed of a calcareous shell having multiple pores called ostia and an apical pore called osculum, for example, Sycon assumes.

Cnidaria:

1. The animal is cylindrical in nature.
2. It has two layers, ectoderm, and endoderm.
3. The mouth is guarded by tentacles.
4. They exhibit extracellular and intracellular digestion.
5. The body consists of nematocysts, used for traping pray, for example, Hydra

 

 

Ctenophora:

1. The animal has 2 layers.
2. It is marine.
3. It has a locomotory organ in the form of comb plates and specialized cells for trapping prey called Suzaid business caul oblast cells, for example, Beroe.

Platyhelminthes :

1. The animal has a flattened body, the body is segmented.
2. The animal is bisexual showing self-autumn fertilization, and survives as an endoparasite, for example, cedes to Taenia.

 

 

Aschelminthes :

1. The animal is unisexual, having a pseudocolor.
2. The female is larger than the male.
3. They have a thick cuticle and survive as endoparasite, for example, Ascaris

 

 

Annelida :

1. The animal is cylindrical in nature, with metameric segmentation.
2. The animal may have red pigment haemoglobin but it is in the plasma.
3. The blood circulation is closed.
4. The animal is bisexual but is not capable of showing self-fertilization, for example, Pheretima posthuma (earthworm)

 

 

Arthropoda :

1. This animal group is the largest having 4 sub-groups.
2. They have open circulation with multi-chambered) sm heart.
3. The sexes are different and fertilization is internal, example Periplaneta americana (cockroach)

 

 

Mollusca:

1. The animal has a soft body covered by the mantle and well protected calcareous shell.
2. The sexes are different and are intermediate between open and closed circulation, for example, Pila

 

 

Echinodermata:

1. The animal has a calcareous endoskeleton with projections.
2. They have blood circulation and a water vascular system.
3. They are marine and feed from the sea bed i.e. benthonic inhabit, for example, Asterias (Starfish).

Hemichordata:

The animal is not under chordates, because they do not have notochord in the matured stage, e.g. Balanoglossus.

Urochordate:

1. The notochord (an elastic rod-like structure situated immediately above the alimentary canal and covered by a sheath.) is limited to the tail region.
2. The animal retains larval character in the adult stage and this phenomenon is called retrogressive metamorphosis example Ascidia

Cephalochordata:

1. The animal has a notochord extended up to the head region.
2. The animal has a tail fin and many characteristics as fish, for example, Amphioxus.

 

 

Vertebrate:

These animals have a backbone called a vertebral column enclosing and protecting the spinal cord.

Cyclostomes:

The animal has a circular mouth with sharp teeth, for example, Myxine.

 

 

Pisces:

1. The group includes all the fish.mat
2. The fishes can be cartilaginous (chondrichthyans) or osteichthyan (bony fish), for example., Shark and Rohu.

 

Amphibia:

1. This group of animals survives both on land and water.
2. They have 3 chambered hearts.
3. They go into hibernation or winter sleep, for example, Frogs.

Reptiles:

1. The animal has an external epidermis.
2. The animal is terrestrial.
3.  The limbs have digited claws.
4. The animal is cold-blooded
5. The ventricle is partially segmented except in crocodiles, which have 4 chambered hearts, for example, Snakes.

Aves:

1. This group is represented by birds, which can be of 2 types, the running bird and the flying bird.
2. They are warm-blooded.
3. The heart is four-chambered.
4. The body is covered with feathers, anterior pair of limbs are modified to produce wings.
5. The lips are modified to produce toothless beaks, for example, Ostrich

 

 

Mammals:

1. The animal group is most advanced with the presence of external hairs, pair of external pinna (ear).
2. The brain is developed that controls all the major functions, the two lobes of the forebrain function in a well-coordinated manner because they are joined by the Corpus callosum.
3. The mammary gland is functional in females for providing nourishment to the developing ones.
4. The most primitive mammals are egg-laying Platypi and myg but the intermediate forms have a pouch, which stores the developing babies called marsupium example Kangaroo.
   While the most developed mammals are placental mammals, where the last developing fetus is provided with nourishment from the mother’s body through the placenta, for example, Human, Ape.

 

 

Question 10. Why is mammal advanced over other animals?
Answer: Mammals have mammary glands, external ears, a diaphragm, a four-chambered heart, and a well-developed brain. They are warm-blooded animals and give birth to young ones.

Hence mammals are the highest group in the animal kingdom.

Chapter 9 Common Machines Review Questions Environment Review Questions MCQs

Question 1. Something that makes a job easier ________________.

1. A machine
2. A simple machine
3. A compound machine
4. A work

Answer: 1. A machine

Question 2. A combination of simple machines is known as ________________.

1. A machine
2. A simple machine
3. A compound machine
4. A work

Answer: 3. A compound machine

Read And Learn More: WBBSE Solutions For Class 6 School Science

Question 3. Something that converts one kind of movement to another is ________________.

1. A machine
2. A simple machine
3. A compound machine
4. A work

Answer: 1. A machine

Question 4. How many simple machines are there?

1. Four
2. Five
3. Six
4. Seven

Answer: 3. Six

Question 5. Which of the following is not considered a simple machine?

1. Wedge
2. Pulley
3. Lever
4. Bicycle

Answer: 4. Bicycle

Question 6. Which is an example of someone using a simple machine to do work?

1. A boy walking along the footpath
2. A girl eats a sandwich
3. A mother pushing a drum up a ramp into a building
4. A father reading a newspaper

Answer: 3. A mother pushing a drum up a ramp into a building

Question 7. The mechanical advantage of a machine is the number of times a machine increases

1. The distance an object is moved
2. The height to which the object is raised
3. The change in direction
4. The force exerted on the machine

Answer: 4. The force exerted on the machine

Question 8. How can a cricket bat be considered a machine?

1. It multiplies force
2. It multiplies distance
3. Both 1 and 2
4. It acts as a wedge

Answer: 3. Both 1 and 2

Question 9. Most of the machines in a human body consisting of bones and muscles are called ________________.

1. Wedges
2. Levers
3. Pulley
4. Complex machines

Answer: 2. Levers

Question 10. Which is not a type of simple machine?

1. Spring
2. Screw
3. Pulley
4. Wedge

Answer: 1. Spring

Question 11. One example of a complex machine is a ________________.

1. Door
2. Pliers
3. Scissors
4. Shovel

Answer: 3. Scissors

Question 12. The fixed point that a lever pivots around are called the ________________.

1. Axle
2. Pulley
3. Gear
4. Fulcrum

Answer: 4. Fulcrum

Question 13. Which body part acts as the fulcrum of levers?

1. Muscles
2. Bones
3. Joints
4. Tendons

Answer: 3. Joints

Question 14. A wheelbarrow is an example of a ________________ class lever.

1. Fourth
2. Third
3. Second
4. First

Answer: 3. Second

Question 15. Which part of the lever supplies the force to move something?

1. Load
2. Fulcrum
3. Effort
4. Axle

Answer: 3. Effort

Question 16.

1. The above figure is an example of
2. Complex machine
3. Lever
4. Screw

Inclined plane

Answer: 2. Complex machine

Question 17. In the above figure which of the following statements is true?

1. AB is the effort arm and BC is the load arm
2. AC is the effort arm and BC is the load arm
3. BC is the effort arm and AC is the load arm
4. BC is the effort arm and AB is the load arm

Answer: 4. BC is the effort arm and AB is the load arm

Question 18. Which of these is an example of a third-class lever?

1. Scissors
2. Fishing pole
3. Pliers
4. Nutcracker

Answer: 2. Fishing pole

Question 19. A simple lever has

1. One load and load-bearing arm
2. One load arm and an effort arm
3. One effort arm and a fulcrum
4. One load arm, one effort arm, and a fulcrum

Answer: 4. One load arm, one effort arm, and a fulcrum

Question 20. Which of the following machines does not have a fulcrum?

1. Inclined plane
2. Nutcracker
3. Scissors
4. Spade

Answer: 1. Inclined plane

Question 21. Which is not a double lever among the following

1. Nail clipper
2. Spoon
3. Nutcracker
4. Scissors

Answer: 2. Spoon

Question 22.

The above figure is a class lever.

1. First
2. Second
3. Third
4. Complex

Answer: 3. Third

Question 23. The wedge, screw, and lever are all

1. Simple machines
2. Complex machines OF
3. Found in the human body
4. None of this eval bris

Answer: 1. Simple machines

Question 24. Study the pictures below. In which case does the effort move through a shorter distance than the load?

1. An only
2. C only
3. A and C only
4. B only

Answer: 3. A and C only

Question 25. If the mechanical advantage of a simple machine is 3, then

1. The output force is 3 times the effort
2. The effort is 3 times the output force
3. The work output is 3 times the work input
4. None of the above

Answer: 1. Output force is 3 times the effort

Question 26. A porter prefers to lift a load on the deck of a truck with a ________________.

1. Lever
2. Wheel
3. Pulley
4. Inclined plane

Answer: 4. Inclined plane

Question 27. Modern luggage is easy to handle because it is fitted with ________________.

1. Pulleys
2. Axle
3. Wheels and long handle
4. Screws

Answer: 3. Wheels and long handle

Question 28. Which of the following machines has a fulcrum at its one end?

1. A pair of scissors
2. A nutcracker
3. A pair of tongs
4. Both 2 and 3

Answer: 4. Both 2 and 3

Question 29. Which simple machine does a flagpole make use of?

1. Screw
2. Inclined plane
3. Pulley
4. Lever

Answer: 3. Pulley

Question 30. The wedge may be used to ________________.

1. B balance a plank
2. Join two planks
3. Lift a plank
4. Split a plank

Answer: 4. Split a plank

Question 31. What are two examples of an inclined plane?

1. Screw and wedge
2. Lever and screw
3. Edge and lever
4. Wheel and axle

Answer: 1. Screw and wedge

Question 32. A wheel with a groove in its rim in which to place a rope is a ________________.

1. Screw
2. Pulley
3. Fulcrum
4. Lever

Answer: 2. Pulley

Question 33. A ________________ is a simple machine used to hold two objects together.

1. Pulley
2. Lever
3. Screw
4. Inclined plane

Answer: 4. Inclined plane

Question 34. Which simple machine would stairs be an example of?

1. A wedge
2. A lever
3. A pulley
4. An inclined plane

Answer: 4. An inclined plane

Question 35. Which of these is an example of a wedge?

1. A skateboard
2. A broom
3. Stairs
4. A butter knife

Answer: 3. Stairs

Question 36. A screw is made up of ________________  wrapped around a rod.

1. Treads
2. Springs
3. Threads
4. Strings

Answer: 3. Threads

Question 37. Which type of simple machine would be found on the bottom of a wagon?

1. Pulley
2. Screw
3. Wedge
4. Wheel and axle

Answer: 4. Wheel and axle

Question 38. The mechanical advantage of an incline depends on the ________________.

1. Mass of the incline
2. The slope of the incline
3. Height of the incline
4. Length of the incline

Answer: 2. Slope of the incline

Question 39. Rust prevention in machine parts can be done by

1. Cleaning only
2. Lubrication only
3. Cleaning followed by proper painting
4. None of the above

Answer: 3. Cleaning followed by proper painting

Question 40. When a screw is turned once around, it advances a distance equal to the ________________.

1. Pitch
2. Diameter of the screw head
3. Load arm
4. Effort arm

Answer: 1. Pitch

Question 41. The human forearm works as

1. First-class lever
2. Second class lever
3. Third class lever
4. A combination of all

Answer: 3. Third-class lever

Question 42. A zipper of a bag is a

1. Pulley
2. Wedge
3. Screw
4. Wheel and axle

Answer: 2. Wedge

Question 43. The oar of a boat is an example of a

1. First-class lever
2. Second class lever
3. Third class lever
4. None of the above

Answer: 2. Second-class lever

Chapter 9 Common Machines Fill In The Blanks

Question 1. To open the lid of a can a spoon acts as a __________.
Answer: Lever

Question 2. The fulcrum of the spade is situated at its __________.
Answer: Far end of the handle

Question 3. The arm that extends from the fulcrum to the point of application of effort is known as the __________
Answer: Effort arm

Question 4. In __________ class lever the fulcrum is placed between the load and the effort.
Answer: First

Question 5. A roller skate could be an example of __________.
Answer: Wheel and axle

Question 6. A machine that utilizes two or more simple machines is called a __________.
Answer: Complex machine

Question 7. A ramp in a parking garage is an example of __________.
Answer: Inclined plane

Question 8. A chef sometimes holds the tip of a knife stationary when chopping food. Held this way, the knife is a complex machine made up of a wedge and a __________.
Answer: Second-class lever

Question 9. Lengthening a ramp will __________ its mechanical advantage.
Answer: Increase

Question 10. As you bite an apple, your front teeth act as a simple machine called a __________.
Answer: Wedge

Question 11. Using energy a machine can change the amount, speed, or __________ of a force to perform an intended action.
Answer: Direction

Question 12. Leverage depends on __________ of the lever.
Answer: Length

Question 13. A __________ pulley is a combination of fixed and movable pulleys.
Answer: Compound

Question 14. An __________ is a rod centered in the wheel.
Answer: Axle

Question 15. The angle of incline is an __________ angle.
Answer: Acute

Question 16. Machines may be employed in __________ environment where it is difficult for a man to work.
Answer: Hazardous

Question 17. A regular __________ after every use can increase the longevity and performance of a machine.
Answer: Cleaning

Question 18. A jar lid is a type of simple machine called __________.
Answer: Screw

Question 19. A wedge has two __________. which meet at a sharp edge.
Answer: Inclined planes

Question 20. A __________ pulley remains fastened to the load itself.
Answer: Movable

Question 21. A lever has a fulcrum and load at the two ends.
Answer: Third class

Question 22. Gears are a form of __________.
Answer: Wheel and axle

Question 23. The distance between two neighboring __________ of a screw is called its pitch.
Answer: Threads

Question 24. There are __________ classes of levers.
Answer: Three

Question 25. A twisted inclined plane wrapped around a rod or pole is a __________.
Answer: Screw

Chapter 9 Common Machines Identify As True Or False

Question 1. A washing machine is a simple machine.
Answer: False

Question 2. Pulley changes the direction of the applied force.
Answer: True

Question 3. Less effort is used to climb a steep inclined plane.
Answer: False

Question 4. In the first class lever, the load is in the center.
Answer: False

Question 5. A nail holds things more firmly than a screw.
Answer: False

Question 6. It is easier to get a screw with a bigger pitch into a piece of wood than a screw with a smaller pitch.
Answer: False

Question 7. Both wheel and axle have a common axis of rotation.
Answer: True

Question 8. An inclined plane reduces the amount of work done compared to pulling something straight up.
Answer: False

Question 9. The axle is a smaller wheel fastened to the wheel at its center.
Answer: True

Question 10. The human arm works as a third-class lever.
Answer: True

Question 11. Using more than one pulley at a time, we get more advantages.
Answer: True

Question 12. There can be levers without a fulcrum.
Answer: False

Question 13. A pair of scissors work as a single lever.
Answer: True

Question 14. The lid of the laptop is connected to the keyboard by a lever.
Answer: True

Question 15. The deployment of machines has led to advantages only in the history of mankind.
Answer: False

Question 16. Complex machines are the building blocks of simple machines.
Answer: False

Question 17. How much load the effort can lift, depends on how many times the wheel is larger than the axle.
Answer: True

Question 18. A leaning ladder is an example of an inclined plane.
Answer: True

Question 19. Pulleys are employed in window blinds.
Answer: True

Question 20. The mechanical advantage of all classes of the lever is the same.
Answer: False

Question 21. In the second class lever, the effort arm is always longer than the load arm.
Answer: True

Question 22. Machines undergo wear and tear as they are put to use on a regular basis.
Answer: True

Question 23. A pulley does not have an axle.
Answer: False

Question 24. Machines reduce the amount of work needed to do a job.
Answer: False

Question 25. To lift a huge block of stone through a certain height, one should choose a crowbar.
Answer: False

Question 26. Decreasing the slant of an inclined plane increases its mechanical advantage.
Answer: True

Question 27. While a screwdriver is used to insert a screw, it acts as a wheel and axle.
Answer: True

Question 28. Machines employ moving parts only.
Answer: False

Question 29. Wheel, axle, and rope or chain make a pulley.
Answer: True

Question 30. When you raise your leg, the knee acts as a fulcrum for the upper leg.
Answer: False

Chapter 9 Common Machines Match The Columns

Answer: A-3,B-2,C-1

 

Answer: A-3,B-1,C-2

Answer: A-4,B-3,C-2

Chapter 9 Common Machines Answer In Words Or A Sentence

Question 1. What sort of angle an inclined plane makes with the ground?
Answer: An acute angle with the ground.

Question 2. Who invented simple machines?
Answer: The Greek philosopher Archimedes.

Question 3. In which class of lever is the direction of the input force opposite to the direction of the output force?
Answer: First class lever.

Question 4. Give three examples of complex machines commonly found in the kitchen.
Answer: A toaster, mixer-grinder, and microwave oven.

Question 5. What type of machine is a pencil sharpener?
Answer: Wheel and axle.

Question 6. Which simple machine turns a Ferris wheel?
Answer: Wheel and axle.

Question 7. A screw is actually another simple machine. Which one?
Answer: Inclined plane.

Question 8. Mention one similarity between second-class and third-class levers.
Answer: Both have a fulcrum at one end.

Question 9. You want to raise a load by using a pulley. In which direction should your pull be to raise it?
Answer: Directed downward.

Question 10. The diagram below shows a crowbar. Calculate the length of the effort arm.
Answer: 

 

EF=(1.50-O.25)m=1.25m

Question 11. How does the advantage of using an inclined plane increase?
Answer: The advantage associated with an inclined plane increases as the length of the inclined edge increases compared to its height making the angle of incline or the slope lesser and lesser.

Question 12. Mention the name of a simple machine that is used by your mother while cooking in the kitchen.
Answer: Tongs.

Question 13. Find out the odd one Screw, ladder, electric vibrator, pulley.
Answer: Electric vibrator: It is a complex machine but others are simple machines.

Question 14. Mention the name of a human body part that acts as a wedge.
Answer: Teeth When we eat, we put our bottom teeth into the middle of the food and break it apart with our top teeth.

Question 15. Mention the name of a part of a bicycle that acts as a simple machine.
Answer: Pedals, back wheel and axle (wheel and axle), or Pedals and chain (Pulley).

Question 16. What is to be applied to a machine to minimize the damage caused by sliding friction between its moving parts?
Answer: Lubricating oil or grease.

Chapter 9 Common Machines Short Answer Type Questions

Question 1. Pens are class-3 levers-justify.
Answer: Pens are class-3 levers since by pivoting them on our hands and holding them in the middle, we get much more control over the nib or the ballpoint.

Question 2. Mention certain disadvantages associated with the use of machines.
Answer: The disadvantages that are associated with the use of machines may be loss of human skill, over-dependence, monotony, destruction, etc.

Question 3. How does the location of the fulcrum influence the working of a lever?
Answer: The closer the fulcrum is to the load being lifted (meaning a shorter load arm compared to an effort arm), the higher shall be the load that the person can lift.

Thus the location of the fulcrum actually influences the mechanical advantage of a lever.

Question 4. What is the purpose of lubrication?
Answer: Movable parts of the machine undergo extensive wear and tear, especially on the surfaces which come in contact while the machine runs.

This leads to the generation of heat. Lubrication cools the parts, makes movements easy, and reduces wear and tear.

Question 5. Why is a screw called a twisted inclined plane?
Answer: The sharp spiral ridges on the body of a screw make an inclined plane. It allows movement from a lower to a higher position but at the same time, it moves in a circle.

Question 6. What is a compound pulley?
Answer: A compound pulley consists of a combination of fixed and movable pulleys.

Question 7. What type of simple machine can you find on the floor of a bathtub?
Answer: The floor of a bathtub slopes towards the drain. This allows water to flow out with the force of gravity. Hence it acts as an inclined plane.

Question 8. Explain the action of the pulley used on flag-poles.
Answer: A fixed pulley is used on flagpoles. The flag is tied to a rope that goes around the pulley. The pulley remains fixed to the top of the flag pole.

By pulling the other end of the rope downwards, the flag is raised.

Question 9. When we bite with our front teeth, our jaw acts as a third-class lever. As we chew with our back teeth, our jaw acts as a second-class lever. Explain how our jaw can act as two different classes of levers.
Answer: The fulcrum of our jaw is located slightly below and in front of our ears. The input force is at the side of the cheek. When we bite, the output force is located in front of the mouth.

The output distance is greater than the input distance. Thus the jaw acts as a third-class lever. When chewing, the output force is near the back of the jaw and the input distance is greater than the output distance.

Hence now the jaw acts as a second-class lever. As a second-class lever, the jaw multiplies force, allowing us to chew and grind food more easily.

Question 10. Why roads on the hills are made winding?
Answer: A road up a hill is an inclined plane. An inclined plane makes work easier along a gradual slope. Hence it becomes easier to ascend a hill on a zigzag road than on a steep road.

The length of the incline or slant length of a zigzag road is more in length compared to a steep road of the same height. Thus the mechanical advantage of a zigzag road is more than that of a steep road.

Question 11. In the following pulley systems, identify the fixed pulleys.
Answer:

Out of the four pulleys shown, pulleys A and C are fastened to the ceiling by means of hooks. Hence these are fixed pulleys.

Question 12. A lever is working as shown in Figure.
What would happen to the mechanical advantage of the lever if the load was moved farther from the fulcrum?
Answer:

If the load was moved farther from the fulcrum, the length of the load arm increased whereas the effort arm remains the same as before. Hence the mechanical advantage of the lever would decrease.

Question 13. Define the fulcrum.
Answer: The point on the lever that does not move while the lever does the work is called the fulcrum (F). Hence it acts as a fixed point of support for the lever.

Question 14. Explain why wedges and screws are actually
Answer: types of inclined plains. A wedge is shaped like a double-inclined plane meeting at a sharp edge. A screw is an inclined plane wrapped around a cylinder to form a spiral.

Like an inclined plane, the wedge and the screw multiply the input force by having it move a greater distance along a sloping edge.

Question 15. Give two examples of a wedge being used in day-to-day life.
Answer: Kitchen knives and razor blades are examples of wedges being used in day-to-day life.

Question 16. In a lever, if the load is moved farther from its fulcrum, how is the effort going to change to lift the load?
Answer: In a lever, if the load is moved farther from the fulcrum, the length of the load arm increases. Thus to lift the same load, the effort shall need to be increased since the effort arm remains the same as before.

Question 17. Explain the actions of the following as levers

1. a fishing rod

2. a nutcracker

3. a spade.
Answer: 1. A fishing rod has a load and the fulcrum on either side of the effort as shown. Hence it acts as a third-class lever.

2. A nutcracker has a fulcrum at one end, effort or force applied at the other end 50 and the force is produced in the middle of the lever. Hence the load is placed between the ep fulcrum and effort. Thus it acts as a second-class lever.

3. A spade is held at the far end which therefore acts as the fulcrum. Effort is given at the center of the handle with the other hand. The blade of the spade works as the load. Thus it acts as a third-class lever.

Question 18. Why is it easier to fix planks using screws rather than nails?
Answer: The sharp spiral-edged ridges on the body of a screw act to hold the planks together.

Nails do not have sharp ridges and so, there is a possibility of slippage under a severe blow in some circumstances leading to separation of the component members. Hence screws are preferred over nails in carpentry.

Question 19. Why is a staircase made like an incline?
Answer: An inclined plane makes work easier when somebody needs to go from a lower place to a higher place.

It actually extends the distance to be traveled horizontally in order to achieve the desired elevation change or rise.

Thus the 913 effort needed as input force becomes smaller for a person while climbing up the stairs. SageIt is worthwhile to mention here that it is easier sv to climb up the stairs if the slope of the incline is less.

Hence, in a house where elderly people reside, the staircase is to be built with less slope or it should be less steep.

Question 20. How is the mechanical advantage of a complex machine determined?
Answer: The mechanical advantage of a complex noho machine is just the product of the mechanical advantages of the simple machines of which it is composed.

Let a complex machine be built with a lever and a pulley with mechanical advantages of 3 and 2 respectively. So the mechanical advantage of the complex machine, so built, shall be 3×2 or 6.

Question 21. Place the correct word in place of? in the figure. Give one example.
Answer: ?= Inclined surface or slant surface.
Example: Wheelchair ramp or slides for children in the playground.

Question 22. Write two differences between simple and complex machines.
Answer:

23. Give two examples of inclined planes as found in our home.
Answer:
1. Ramp in the main gate/door

2. Stairs or

3. Slanted roof

Chapter 9 Common Machines Long Answer Type Questions

Question 1. Discuss some of the utilities of using machines.
Answer:

Utilities Of Machine

We cited quite a few examples of machines in the previous section. All these machines have one thing in common when you apply a force to them, they increase their size and apply a greater force somewhere else.

You can’t cut meat with your hand alone, but if you push down on a knife, the long handle and the sharpened blade magnify the force you apply with your hand, and the meat slices effortlessly.

When you pound a nail with a hammer, the handle increases the force you apply.

And because the head of the hammer is bigger than the head of the nail, the force you apply is exerted over a smaller area with much greater pressure and the nail easily enters the wood.

Try pushing in a nail with your finger and you’ll appreciate the advantage a hammer gives you.

Living in a world without machines is now almost impossible to imagine. Without even the simplest machines, many tasks that we do every day would be almost impossible.

Machines make it easier for humans to perform everything from the simplest to the most complicated of tasks.

A washing machine, for instance, saves a lot of time as we can do other things while the clothes are being washed.

Vacuum cleaners save a lot of time and energy in cleaning the floors or carpets. A sewing machine is also a very useful machine. Sewing by hand is a very slow job requiring a lot of patience.

Using a sewing machine helps to stitch clothes quickly and neatly. Let us now learn about the advantages of the use of machines.

Question 2. What is a simple machine? How many types of simple machines are there? Name them.
Answer:

The following are the advantages of the use of machines :

1. Use of natural forces:

Machines have made it possible to harness the forces of nature in

Simple machine:

in earlier times when a human being needed to move something heavy, he or she probably picked up a long stick, stuck it under the edge of the heavy object and stuck it under the edge of the heavy object, and then pushed it down on the other end of the stick.

The service of man. Man can fly in airplanes, he can connect continents in seconds, and electricity can be generated from sunrays, waterfalls, winds, etc. All these have been made possible with the aid of machines.

2. Heavy and delicate work made simple :

Tasks that are too heavy or too delicate for human muscles to do can be done easily by a machine. A crane can lift loads beyond the human capacity. Without the aid of machines, such jobs would not have been done.

3. Faster and more accurate work :

Only machines are capable of mass production, that too accurately, without a break and for a continuous duration.

While man can make only a few articles in a day by himself, machines employed in factories can make thousands per day for years together with extreme accuracy.

A human being, for example, can not paint exactly the same picture twice. But a machine can turn out thousands of identical articles. This has also resulted in the availability of durable articles at a much cheaper price.

4. More employment:

The introduction of machines in the modern society has created many new occupations. It has thus widened the scope of employment.

5. Hazardous work environment:

Human beings are relieved of all disagreeable and unpleasant jobs in hazardous environments by suitably deploying machines to do the same.

However, it must be remembered that machines are also associated with certain evils. These may be loss of human skill, over-dependence, monotony, destruction, and so on.

Question 3. Define lever. What is meant by First class, Second class, and Third class levers? Explain with diagrams.
Answer:

Idea of Lever

Levers were probably the first machines used by human beings. It is a long tool such as a pole or a rod put under an object to lift it.

Levers are all around us. The handle of the spoon is a lever since it makes it easier for us to open the lid of a can. The lever becomes more efficient when combined with a fulcrum.

 

The fulcrum is another object, maybe a rock, used to give alginate Lana to tone support or brace under the long tool. This gives the long pole something to push down against.

Let us take another example to get the matter clear. When you sit on a see-saw, you have probably found out that you need to sit further from the balance point if the person at the opposite end is heavier than you.

The balance or pivot point acts as the fulcrum here. The further away from the fulcrum you sit, the more you can multiply the force of your weight.

If you sit a long way from the fulcrum, you can even easily lift a much heavier person sitting at the other end provided of course they sit very close to the fulcrum on their side.

The force you apply with your weight is called the effort. The fulcrum produces a bigger force to lift the load (here it is the weight of the other person).

The words “effort” and “load” are associated with the working of the lever. However, the important thing fo to remember about levers is that the force you produce (which drives the load) is bigger than the force you apply as effort.

Some examples of levers are:

Door handles the claws of a hammer (for removing nails), light switches, bottle openers, tongs, knives, screwdrivers, wrenches, scissors, and hinges.

The force that is used on the lever is called the effort (E).

The weight that is moved or lifted by the lever is called the load (L).

The point on the lever that does not move while the lever does the work is called the fulcrum (F). Hence it acts as a fixed point of support for the lever.

Classes of Lever

All levers give leverage, but not all of them work the same way. There are actually three different kinds of levers (sometimes known as classes).

The class of a lever depends on the relative positions of the efforts, load, and fulcrum.

First-class or Class-1 levers

In a First class lever, the effort or force we apply is on the opposite side of the fulcrum to the force the lever produces.

Hence the fulcrum is placed between the effort and the load. See-saw, beam balance, and scissors are all first-class levers.

Hence the load is placed between the fulcrum and the effort. Nutcrackers, bottle openers,s, and wheelbarrows are all examples of Second class levers.

 

 

 

Second-class or Class-2 levers

A Second class lever is arranged in a different way, with the fulcrum at one end. The effort or force is applied at the other end and the force is produced in the middle of the level.

 

 

Third-class or Class-3 levers

A Third class lever, like a Second class lever, has the fulcrum at one end.

But the two forces switch around. Hence the effort or force is applied at the middle and the force is produced at the opposite end. Thus the effort is placed between the fulcrum and the load.

Third Class levers reduce the force you apply, giving you much greater control. Stapler, fishing
rod and tongs are examples of Third Yowlega pro-class levers.

 

Question 4. What is an inclined plane? How is it useful?
Answer:

Inclined Plane

The inclined plane is simply a ramp whose one end is higher than the opposite end. This allows things to go from a low place to a higher place without much effort.

But the load has to be moved over a longer distance as compared to pulling it up vertically. Whether the inclined plane is long or short, the amount of work done shall be the same.

Thus an inclined plane does not decrease work but makes it easier. On the other hand, gravity makes it easier to move an object down a ramp than up that ramp.

A slide in the children’s park, a d-leaning ladder, a staircase, and a sloping wooden plank (Fig. 9.22) are examples of inclined planes.

The acute angle that the inclined plane makes with the ground is called the angle of incline (Fig. 9.23) or slope.

If the slope of the inclined plane is low meaning that a smaller angle between the ground and the plane, then it is easier to climb up.

The mechanical advantage of an inclined. the plane is linked to the slope or angle of the incline.

 

 

The mechanical advantage \(=\frac{\text { Length }}{\text { Height }}\)

It is apparent that the length of the inclined plane is greater than its height. Hence, by applying a small effort, the big load may be raised. The inclined plane has a mechanical advantage always greater than 1.

Uses of the inclined plane

1.  As loading ramps to load and unload goods on trucks, ships, planes, etc. FEAR
2. As wheelchair ramps for aged, invalid persons and patients.
3.  As staircase and escalators.
4. As conveyor belts.

Question 5. What is a pulley? How is a fixed pulley different from a movable pulley? Explain with diagrams.
Answer:

The Pulley

The pulley is actually a modified version of a wheel and axle that is combined with a rope, chain or other cord passing through a groove to allow moving something up and down or back and forth.

The rod that passes through the center of the pulley is called the axle. The pulley rotates freely about the axle.

The pulley can be combined with other pulleys to reduce the amount of work necessary to lift huge amounts of weight or to lower them down.

 

It can also make moving something such as a flag up the pole convenient to do from the ground. It changes the direction of the applied force necessary to do the work.

You pull down on the rope, but the flag goes up. Pulleys are used in window blinds and drapery to move them up and down or back and forth.

Pulleys are also used on ships to raise and lower sails, in the industry to raise and lower heavy cargo, or on cranes for use in moving construction equipment.

Elevators also use pulleys to move the car up and unban down from floor to floor.

There are three types of pulleys-fixed, movable, and compound. A fixed pulley is fastened to some support by means of a hook.

 

 

A very common use of a single fixed pulley is in lifting water from wells. A movable pulley is one that remains fastened to the load itself. This type of pulley is free to move up and down.

Examples of movable pulleys include construction cranes, modern elevators, and some types of weight-lifting machines at the gym.

The third type of pulley is the compound pulley, which consists of combinations of fixed and movable pulleys.

 

 

 

Question 6. Why do machines require maintenance? Elaborate a few simple steps to follow for the maintenance of machines.
Answer:

Maintenance Of Machines

Machines undergo wear and tear as they are put to use on a regular basis.

If not taken care of properly, this may lead to permanent damage to the component parts, discoloration or rusting, malfunctioning, decreased efficiency, and above all, serious danger to the person operating the machine.

Hence regular upkeep and maintenance on the overall functionality and condition of machines are a must to keep the continuity of what is expected and the standard performance of the machines.

Simple steps to follow for maintenance of machines :

1. Keep it routine:

Just like the annual check-up with a physician, a regular check-up has to be made to inspect the conditions of the parts of a machine in order to ensure desired performance it.

This is an absolute emergency for heavy and complex machines.

2. Cleaning:

Routine cleaning after every use increases the longevity and performance of a machine many times.

3. Lubrication:

Lubrication of moving parts using grease or oil is an important part of regular machine maintenance. The lubrication procedure may be repeated in line with the degree of usage.

4. Rust prevention:

Metallic parts of a machine shall be protected from rusting caused by moisture ingress by suitably applying an anti-rust synthetic enamel paint or oil paint.

5. Don’t overwork the machine:

It is always advisable that the stated performance of a machine should not be exceeded at any point in time.

Overwork leads to greater wear and tear and finally to the shorter life span of the machine under consideration.

Question 7. The sewing machine is a complex machine- explain.
Answer: A sewing machine has several parts such as the main driving wheel, small driving wheel, needle, foot pedal, etc. which are made up of many simple machines such as wheel and axle, wedge, lever, and screw.

The main driving wheel and the small driving wheel work on the basis of wheel and axle. A sewing machine’s needle works on the basis of the wedge. The foot pedal works on the basis of the lever.

Also, a sewing machine employs a number of screws which play a vital role in its functioning. Thus it is a complex machine made up of many simple machines.

Question 8. Compare a single fixed pulley with a single movable pulley.
Answer: Comparison of the single fixed pulley and single movable pulley

Question 9. Explain what is meant by the Two ramps shown in the figure. Which ramp would be more convenient to use to move a heavy barrel up into a truck?

1. mechanical advantage 1

2. mechanical advantage > 1 and

3. mechanical advantage <1 for a simple lever.

Answer:

 

\(\text { mechanical advantage }(M A)=\frac{\text { Load }}{\text { Effort or Input force }}\)

If MA=1, the input force to be applied to the lever has to be the same as the load.

If MA>1, less input force needs to be applied to the lever compared to the load to be driven. Thus the work becomes easier.
If MA<1, more or greater magnitude of input force is required to be put into the lever to drive the load.

Ramp (a) has a more mechanical advantage compared to ramp (b) since for the same height, the length of the slant surface of ramp (a) is more than that of ramp (b).

Thus for some elevation changes, the distance to be traveled horizontally is more in the case of ramp (a). Thus the effort or force needed to push the barrel up is lesser in the case of ramp (a).

Chapter 8 The Human Body Heart Review Questions Environment Review Questions MCQs

Question 1. An example of a system is

1. Blood
2. Nerve
3. Cardiovascular
4. Cell

Answer: 3. Cardiovascular

Question 2. The __________ is responsible for pumping blood throughout our body.

1. Heart
2. Kidney
3. Lymph node
4. Brain

Answer: 1. Heart

Read And Learn More: WBBSE Solutions For Class 6 School Science

Question 3. The heart is located in the middle of

1. Blood vessels
2. Lungs
3. Organs
4. Chest

Answer: 4. Chest

 

Question 4. The number of chambers in our heart is

1. 2
2. 3
3. 4
4. 5

Answer: 3. 4

Class 6 Science Question Answer WBBSE

Question 5. When the heart is situated on the right side of the chest, the condition is known as

1. Dextrocardia
2. Cardiac muscle
3. Illness
4. Pathology

Answer: 1. Dextrocardia

Question 6. The membrane surrounding the heart is known as

1. Myocardium
2. Pericardium
3. Cardium
4. Endocardium

Answer: 2. Pericardium

Question 7. The heart of a normal the rate of about adult human beats at the rate of about __________ per minute.

1. 90
2. 72
3. 60
4. 100

Answer: 2. 72

Question 8. The two top chambers of the heart are called the

1. Atrium
2. Ventricle
3. Atria
4. None of the above

Answer: 3. Atria

Question 9. Running down the middle of the heart is a thick wall of muscle called the

1. Septum
2. Membrane
3. Both ‘a’ and ‘b’ correct
4. None of the above

Answer: 1. Septum

Class 6 Science Question Answer WBBSE

Question 10. Mitral valves are

1. Tricuspid
2. Aortic
3. Semilunar
4. Bicuspid

Answer: 4. Bicuapid

Question 11. The __________ side of your heart sends oxygen-rich blood out to the body.

1. Right
2. Anterior
3. Left
4. Posterior

Answer: 3. Left

Question 12. The heart receives blood from the upper body through

1. Superior vena cava
2. Inferior vena cava
3. Arteries
4. Veins

Answer: 1. Superior vena cava

Question 13. Sino-atrial node is situated in the

1. Left ventricle
2. Left atrium
3. Right ventricle
4. Right atrium

Answer: 4. Right atrium

Question 14. Arteriosclerosis means the arteries become thickened and are no longer properly

1. Dependable
2. Flexible
3. Reliable
4. Controllable

Answer: 2. Flexible

Question 15. A blood clot or other blockage cuts blood flow to a part of the heart and causes

1. Anaemia
2. Hemorrhage
3. Heart attack
4. All the above

Answer: 3. Heart attack

Class 6 Science Question Answer WBBSE

Question 16. A bicuspid valve is present in

1. Left atrium
2. Right atrium
3. Aorta
4. Sinus venous

Anawer: 1. left atrium

Question 17. In between arterioles and venules there lies

1. Aorta
2. Heart
3. Superior vena cava
4. Capillaries

Answer: 4. Capillaries

Question 18. Relaxation of the heart is termed as

1. Polystole
2. Systole
3. Diastole
4. Tryastole

Answer: 3. Diastole

 

Chapter 8 The Human Body Heaet Fill In The Blanks

Question 1. An __________ is an organization of several different kinds of tissues so arranged that together they can perform a special function.
Answer: Organ

Question 2. The circulatory system consists of the heart __________, blood vessels, arteries, and veins.
Answer: Blood

Question 3. Your heart beats around 100000 times a __________.
Answer: Day

Class 6 Science Question Answer WBBSE

Question 4. The __________ is responsible for pumping blood throughout our body.
Answer: Heart

Question 5 Heart is made up of __________ muscles.
Answer: Cardiac

Question 6. In 99% of the cases, the heart is located the on __________ side of the chest.
Answer: Left

Question 7. __________ fluid prevents friction between the pericardium and the heart.
Answer: Pericardial

Question 8. The heart wall consists of the myocardium and the __________ endocardium.
Answer: Epicardium

Question 9. The __________ side of your heart receives blood from the body and pumps it to the lungs.
Answer: Right

Question 10. The heart of a normal adult human beats at the rate of about __________ per minute.
Answer: 72

Question 11. The __________ are the chambers that fill with the blood returning to the heart from the body and lungs.
Answer: Atria

Question 12. The two chambers on the bottom are called the __________
Answer: Ventricles

Question 13. Heart valves all work to keep the blood flowing __________
Answer: Forward

Question 14. The movement of the blood through the heart and around the body is called __________.
Answer: Circulation

Question 15. A healthy heart makes a __________ sound with each beat.
Answer: Lub-Dub

Question 16. From the right atrium, the blood descends into the __________ right ventricle through the, valve.
Answer: Tricuspid

Class 6 WBBSE Science Question Answer

Question 17. __________ is an irregular or abnormal heartbeat.
Answer: Arrhythmia

Question 18. __________ Heart disease is a type of birth defect that causes problems with the heart at birth.
Answer: Congenital

 

Chapter 8 The Human Body Heart Identify As True Or False

Question 1. Organs are more complex units than tissues.
Answer: True

Question 2. The job of the circulatory system is to break down and absorb food.
Answer: False

Question 3. The kidneys are responsible for pumping blood throughout our body.
Answer: False

Question 4. Red blood cells carry oxygen around the body.
Answer: True

Question 5. It takes about 20 seconds for a red blood cell to circle the whole body.
Answer: True

Question 6. The heart is located a little to the left of the middle of your chest, and it is about the size of your fist.
Answer: True

Question 7. The heart is surrounded by a membrane called the myocardium.
Answer: False

Question 8. The heart of a normal adult human beats at the rate of about 72 per minute.
Answer: True

Class 6 WBBSE Science Question Answer

Question 9. The heart has two left ventricles and a right ventricle.
Answer: False

Question 10. Two of the heart valves are the bicuspid valve and the mitral valve.
Answer: False

Question 11. The movement of the blood through the heart and around the body is called circulation.
Answer: True

Question 12. A healthy heart makes a lub-dub sound with each beat.
Answer: True

Question 13. The human circulatory system is really a two-part system whose purpose is to bring oxygen-bearing blood to all the tissues of the body.
Answer: True

Question 14. From the right atrium, the blood descends into the right ventricle through the tricuspid valve.
Answer: True

Question 15. People with angina feel pain in the chest which means the brain isn’t getting enough blood.
Answer: False

 

Chapter 8 The Human Body Heart Match The Columns

 

 

 

 

Answer: A-4,B-5,C-2,D3

 

Answer: A-5,B-4,C-1,D-3

 

Chapter 8 The Human Body Heart Answer In Words Or A Sentence

Question 1. What are the functions of the circulatory system? The job of the circulatory system is to
Answer: move blood, nutrients, oxygen, carbon dioxide, and hormones, around the body.

Question 2. State the function of the heart in our body.
Answer: The heart is responsible for pumping blood throughout our body.

Question 3. What type of muscle makes the heart?
Answer: Cardiac Muscle.

Class 6 WBBSE Science Question Answer

Question 4. How many chambers are there in our hearts?
Answer: Four chambers.

Question 5. Name the middle layer of the heart wall.
Answer: It is the myocardium.

Question 6. Name the valve present between the right atrium 20h and the right ventricle.
Answer: Tricuspid valve.

Question 7. Write the full form of the AV node.
Answer: atrioventricular node.

Question 8. What are systole and diastole ?
Answer: The term systole refers to contraction and the term diastole refers to relaxation.

Question 9. What is arteriosclerosis?
Answer: It is a diseased condition caused by the hardening of arteries.

Question 10. What is a heart attack?
Answer: It is an abnormal condition when a blood clot or other blockage cuts blood flow to a part of the heart.

 

Chapter 8 The Human Body Heart Short Answer Type Questions

Question 1. Write the functions and components of the circulatory system.
Answer: The job of the circulatory system is to move blood, nutrients, oxygen, carbon dioxide, and hormones around the body. It consists of the heart, blood, and blood vessels, arteries-veins and capillaries.

Question 2. State the location of the heart in our body.
Answer: The heart is located a little to the left of the middle of our chest and it is about the size of our fist. It sits behind our ribs on the left side of our body just next to our sternum.

Question 3. What are the four chambers of our heart?
Answer: The human heart is divided into 4 chambers or parts: the two ventricles (lower parts) and two atria (upper parts).

WBBSE Class 6 Science Question Answer

Question 4. What is dextrocardia?
Answer: Normally, the heart is located on the left side of the chest. However, in rare cases, the heart can also be found on the right side of the chest; this condition is known as dextrocardia.

Question 5. What are the components of the heart wall?
Answer: The heart wall consists of the epicardium (outer layer), the myocardium (middle layer comprised of cardiac muscle tissue), and the endocardium (inner lining of the myocardium that covers the heart valves).

Question 6. What are heart sounds?
Answer: A healthy heart makes a lub-dub sound with each beat. This sound comes from the valves shutting on the blood inside the heart.

The first sound (the lub) happens when the mitral and tricuspid valves close.

The next sound (the dub) happens when the aortic and pulmonary valves close after the blood has been squeezed out of the heart.

Question 7. What is a pulse?
Answer: A pulse represents the tactile arterial palpation of the heartbeat by trained fingertips.

The pulse may be palpated in any place that allows an artery to be compressed against a bone, such as at the neck (carotid artery), on the inside of the elbow (brachial artery), at the wrist (radial artery), etc.

Question 8. What is heart muscle?
Answer: Cardiac muscle (heart muscle) is an involuntary, striated muscle that is found in the walls and histological foundation of the heart, specifically the myocardium.

Question 9. What is a systemic loop of circulation?
Answer: In the systemic loop, the blood circulates into the body’s systems, bringing oxygen to all its organs, structures, and tissues and collecting carbon dioxide waste.

Question 10. What is a pulmonary loop of circulation?
Answer: In the pulmonary loop, the blood circulates to and from the lungs, to release the carbon dioxide and pick up new oxygen.

Question 11. What is atherosclerosis?
Answer: It is a build-up of cholesterol and fat that makes the arteries narrower so less blood can flow through. Those build-ups are called plaque.

Question 12. What is arrhythmia?
Answer: Arrhythmia is an irregular or abnormal heartbeat. This can be a slow heartbeat (bradycardia), a fast heartbeat (tachycardia), or an irregular heartbeat.

Question 13. Your friend suffers from breathing trouble while playing and therefore, prefers to
Answer: Sit idle. What may be his disease in your opinion He may be suffering from either congenital heart disease or asthma.

 

Chapter 8 The Human Body Heart Long Answer Type Questions

Question 1. Write about the electrical conduction system of the heart.
Answer: 

Conduction system:

An electrical impulse travels through the heart and initiates contractions in the chambers.

The heart’s “spark plug” is an area of specialized heart tissue called the sino- atrial node (SA node), which is located in the right atrium.

Each time the SA node “fires”, an electrical impulse is generated, that travels through the right and left atria, signaling these chambers to contract and pump blood into the ventricles.

WBBSE Class 6 Science Question Answer

Isidore to The impulse then travels into another area of specialized heart tissue called the atrioventricular node (AV node), which is located between the atria and the ventricles.

The 2 electrical impulses are conducted through the AVA node and wire-like pathways (Bundle of His and d Purkinje fibers) to the ventricles, signaling the ventricles to contract and pump blood into the lungs and throughout the body.

 

 

As the SA node maintains the pace of the heartbeat, it is also known as a natural pacemaker. If it does not function, an artificial pacemaker has to be implanted.

The normal sequence of electrical activation of the chambers of the heart is called sinus rhythm. It occurs each time the heart beats, usually about 60 to 80 times every minute.

In a normal heartbeat, the atria contract simultaneously while the ventricles relax. Then, the ventricles relax, and the atria contract.

The term systole refers to contraction and the term diastole refers to relaxation. A heartbeat consists of the systole and diastole of the atria and the systole and diastole of the ventricles.

Problems of the Heart: You know how important your heart is, so it is no wonder people worry when they hear someone has heart problems.

Heart disease, also called cardiovascular disease, mainly affects older. people and means that there are problems with the heart and blood vessels.

You might know someone who has cardiovascular disease because several people in our society have some form of it.

This disease includes a variety of problems, including high blood pressure, hardening of the arteries, chest pain, heart attacks, and strokes.

Milanese te The heart is the center of the cardiovascular system. Through the body’s blood vessels, the d heart pumps blood to all of the body’s cells.

WBBSE Class 6 Science Question Answer

The blood carries oxygen, which the cells need. Cardiovascular disease is a group of problems that occur when the heart and blood vessels are not working the way they should.

 

 

Here are some of the problems that go along with cardiovascular disease:

1. Arteriosclerosis:

Also called hardening of the arteries, arteriosclerosis means the arteries become thickened and are no longer flexible.

2. Atherosclerosis:

A buildup of cholesterol things a risk factor. Some of these risk factors a and fat which makes the arteries narrower, so less blood can flow through. Those buildups are called plaque.

3. Angina:

People with angina feel pain in the chest which means the heart muscle is not getting enough blood and oxygen.

4. Arrhythmia:

It is an irregular or abnormal er heartbeat. This can be a slow heartbeat en (bradycardia), a fast heartbeat (tachycardia), or an irregular heartbeat.

5. Heart attack:

When a blood clot or other blockage cuts blood flow to a part of the heart.

6. Ischemic heart disease:

A pathological condition of the heart muscle caused by lack of oxygen supply marked by pain and discomfort.

7. Heart valve disease:

It occurs when one or more of the four valves in the heart are not working properly. Heart valves help to ensure that the blood being pumped through the heart keeps flowing forward.

A disease of the heart valves (e.g., stenosis, mitral valve prolapse) makes it difficult for the heart to work efficiently.

WBBSE Class 6 Science Question Answer

8. Congenital heart disease:

It is a type of birth defect that causes problems with the heart at birth and occurs in about one out of every 100 live births.

Some of the most common types of congenital heart disease include atrial septal defects (ASD) and ventricular septal defects (VSD).

which occurs when the walls that separate the right and left chambers of the heart are not completely closed and consequently, there is a hole in the wall.

Babies born with congenital heart disease (ASD) may not have symptoms. When they grow up, adults may notice symptoms such as shortness of breath, heart palpitations, fatigue, swelling in the legs, feet, or abdomen, etc.

Symptoms of VSD include a bluish tinge to the skin, lips, and fingernails, along with poor feeding, poor weight gain, and fast breathing.

Heart disease is not contagious-we cannot catch it like we can the flu or a cold. Instead, certain things increase a person’s chances of getting cardiovascular disease.

Doctors call these people who can’t do anything about are like being older and having other people in the family who have had the same problems.

But people do have control over some risk factors smoking, having high blood pressure, being overweight, and not exercising can increase the risk of getting cardiovascular disease.

Question 2. State the importance of systemic and pulmonary loops of circulation.
Answer:

The circulation of blood:

The human circulatory system is really a two-part system whose purpose is to bring oxygen-bearing blood to all the tissues of the body.

When the heart contracts it pushes the blood out into two major loops or cycles.

In the systemic loop, the blood circulates into the body’s systems, bringing oxygen to all its organs, structures, and tissues and collecting carbon dioxide waste.

In the Pulmonary loop, the blood circulates to and from the lungs, to release the carbon dioxide and pick up new oxygen.

The systemic cycle is controlled by the left side of the heart, and the pulmonary cycle by the right side of the heart. Let’s look at what happens during each cycle.

The systemic loop begins when the oxygen-rich blood coming from the lungs enters the upper left chamber of the heart, the left atrium.

As the chamber fills, the blood flows down through the mitral valve into the relaxing left ventricle. When the ventricles contract during a heartbeat, the blood on the left side is forced into the aorta.

This largest artery of the body is an inch wide. The blood leaving the aorta brings oxygen to all the body’s cells through the network of ever-smaller arteries and capillaries.

The used blood from the body returns to the heart through the network of veins. All of the blood from the body is eventually collected into the two largest veins the superior vena cava.

Which receives blood from the upper body, and the inferior vena cava, which receives blood from the lower body region. Both venae cavae empty the blood into the right atrium of the heart.

From here the blood begins its journey through the pulmonary cycle. From the right atrium, the blood descends into the right ventricle through the tricuspid valve.

When the ventricles contract, the blood in the right ventricle is pushed into the pulmonary artery that branches into two main parts one going to the left lung, and one to the right lung.

The fresh, oxygen-rich blood returns to the left atrium of the heart through the pulmonary veins.

Although the circulatory system is made up of two cycles, both happen at the same time. The contraction of the heart muscle starts in the two atria, which push the blood into the ventricles.

Then the walls of the ventricles squeeze together and force the blood out into the arteries: the aorta to the body and the pulmonary artery to the lungs.

Afterward, the heart muscle relaxes, allowing blood to flow in from the veins and fill the atria again.

In healthy people, the normal (resting) heart rate is about 72 beats per minute, but it can go much higher during strenuous exercise.

Scientists have estimated that it takes about 30 seconds for a given portion of the blood to complete the

Entire cycle:

from lungs to heart to body, back to the heart, and out to the lungs.

Conduction system:

An electrical impulse travels through the heart and initiates contractions in the chambers.

The heart’s “spark plug” is an area of specialized heart tissue called the sino- atrial node (SA node), which is located in the right atrium.

Each time the SA node “fires”, an electrical impulse is generated, that travels through the right and left atria, signaling these chambers to contract and pump blood into the ventricles.

Isidore to The impulse then travels into another area of specialized heart tissue called the atrioventricular node (AV node), which is located between the atria and the ventricles.

The 2 electrical impulses are conducted through the AVA node and wire-like pathways (Bundle of His and d Purkinje fibers) to the ventricles, signaling the ventricles to contract and pump blood into the lungs and throughout the body.

 

 

As the SA node maintains the pace of the heartbeat, it is also known as a natural pacemaker. If it does not function, an artificial pacemaker has to be implanted.

The normal sequence of electrical activation of the chambers of the heart is called sinus rhythm. It occurs each time the heart beats, usually about 60 to 80 times every minute.

In a normal heartbeat, the atria contract simultaneously while the ventricles relax. Then, the ventricles relax, and the atria contract.

The term systole refers to contraction and the term diastole refers to relaxation. A heartbeat consists of the systole and diastole of the atria and the systole and diastole of the ventricles.

Problems of the Heart: You know how important your heart is, so it is no wonder people worry when they hear someone has heart problems.

Heart disease, also called cardiovascular disease, mainly affects older. people and means that there are problems with the heart and blood vessels.

You might know someone who has cardiovascular disease because several people in our society have some form of it.

This disease includes a variety of problems, including high blood pressure, hardening of the arteries, chest pain, heart attacks, and strokes.

Milanese te The heart is the center of the cardiovascular system. Through the body’s blood vessels, the d heart pumps blood to all of the body’s cells.

The blood carries oxygen, which the cells need. A cardiovascular disease is a group of problems that occur when the heart and blood vessels are not working the way they should.

 

Question 3. What are congenital heart diseases?
Answer:

Problems of the Heart:

You know how important your heart is, so it is no wonder people worry when they hear someone has heart problems. Heart disease, also called.

Cardiovascular disease: 

Mainly affects older. people and means that there are problems with the heart and blood vessels.

You might know someone who has cardiovascular disease because several people in our society have some form of it.

This disease includes a variety of problems, including high blood pressure, hardening of the arteries, chest pain, heart attacks, and strokes.

Milanese te The heart is the center of the cardiovascular system. Through the body’s blood vessels, the d heart pumps blood to all of the body’s cells.

The blood carries oxygen, which the cells need. Cardiovascular disease is a group of problems that occur when the heart and blood vessels are not working the way they should.

 

 

Here are some of the problems that go along with cardiovascular disease:

1. Arteriosclerosis:

Also called hardening of the arteries, arteriosclerosis means the arteries become thickened and are no longer flexible.

2. Atherosclerosis:

A buildup of cholesterol things a risk factor. Some of these risk factors a and fat which makes the arteries narrower, so less blood can flow through. Those buildups are called plaque.

3. Angina:

People with angina feel pain in the chest which means the heart muscle is not getting enough blood and oxygen.

4. Arrhythmia:

It is an irregular or abnormal er heartbeat. This can be a slow heartbeat en (bradycardia), a fast heartbeat (tachycardia), or an irregular heartbeat.

5. Heart attack:

When a blood clot or other blockage cuts blood flow to a part of the heart.

6. Ischemic heart disease:

A pathological condition of the heart muscle caused by lack of oxygen supply marked by pain and discomfort.

7. Heart valve disease:

It occurs when one or more of the four valves in the heart are not working properly. Heart valves help to ensure that the blood being pumped through the heart keeps flowing forward.

A disease of the heart valves (e.g., stenosis, mitral valve prolapse) makes it difficult for the heart to work efficiently.

8. Congenital heart disease:

It is a type of birth defect that causes problems with the heart at birth and occurs in about one out of every 100 live births.

Some of the most common types of congenital heart disease include atrial septal defects (ASD) and ventricular septal defects (VSD).

which occurs when the walls that separate the right and left chambers of the heart are not completely closed and consequently, there is a hole in the wall.

Babies born with congenital heart disease (ASD) may not have symptoms. When they grow up, adults may notice symptoms such as shortness of breath, heart palpitations, fatigue, swelling in the legs, feet, or abdomen, etc.

Symptoms of VSD include a bluish tinge to the skin, lips, and fingernails, along with poor feeding, poor weight gain, and fast breathing.

Heart disease is not contagious-we cannot catch it like we can the flu or a cold. Instead, certain things increase a person’s chances of getting cardiovascular disease.

Doctors call these people who can’t do anything about are like being older and having other people in the family who have had the same problems.

But people do have control over some risk factors smoking, having high blood pressure, being overweight, and not exercising can increase the risk of getting cardiovascular disease.

 

Chapter 8 The Human Body Blood Review Questions Environment Review Questions MCQ

Question 1. Blood is a type of

1. Tissue
2. Organ
3. Cell
4. System

Answer: 1. Tissue

Question 2. Red blood cells are created inside

1. Heart
2. Kidney
3. Bone marrow
4. Liver

Anawer: 3. Bone marrow

Question 3. The average blood volume in the adult body is about

1. 2 liters
2. 3 liters
3. 5 liters
4. 1 liter

Answer: 3. 5 liters

Question 4. Oxygen is transported throughout the body

1. White blood cells
2. Red blood cells
3. Platelets
4. Plasma

Answer: 2. Red blood cells

Question 5. The color of our plasma is

1. Reddish
2. Greenish
3. Bluish
4. Yellowish

Answer: 4. Yellowish

Question 6. The color of RBC is due to

1. Chlorophyll
2. Haemocyanin
3. Haemoglobin
4. None of the above

Answer: 2. Haemocyanin

Question 7. WBC is also called

1. Neutrophil
2. Basophil
3. Leucocyte
4. Erythrocyte

Answer: 3. Leucocyte

Question 8. Platelets help in

1. Blood clotting
2. Controlling blood sugar
3. Immunity
4. Oxygen carriage

Answer: 1. Blood clotting

Question 9. A lower-than-normal number of red cells in the

1. Malaria
2. Leukemia
3. AIDS
4. Anaemia

Answer: 4. Anaemia

Question 10. The function of WBC is

1. To carry O2 from the lungs to different parts of
2. to build up immunity
3. to coagulate blood
4. none of these

Answer: 2. to build up immunity

 

Chapter 8 The Human Body Blood Fill in the Blanks

Question 1. _________ blood cells fight infections.
Answer: White

Question 2. _________ is a yellowish liquid that carries nutrients and proteins throughout the body.
Answer: Plasma

Question 3. Bone marrow makes the _________ cells.
Answer: Blood

Question 4. Red blood cells are also known as _________
Answer: Erythrocytes

Question 5 Granulocytes may be of 3 different types Neutrophil, _________ and Basophil.
Answer: Eosinophil

Question 6. There are two types of lymphocytes _________ cells and T cells.
Answer: B

Question 7. Rh protein was first found in _________ monkeys.
Answer: Rhesus

Question 8. _________ are cancers of the cells that produce WBCs.
Answer: Leukaemia

 

Chapter 8 The Human Body Blood Identify As True Or False

Question 1. Bone marrow makes blood cells.
Answer: True

Question 2. Plasma is a type of blood cell.
Answer: False

Question 3. Mature RBCs of our body are multinucleated.
Answer: False

Question 4. While blood cells are bigger than red blood cells.
Answer: True

Question False

Question 6. Platelets are cell fractions.
Answer: True

Question 7. Plasma is yellowish in color.
Answer: True

Question 8. Getting blood of the wrong type can make a person sick.
Answer: True

Question 9. Anaemia is accompanied by an increase in the amount of hemoglobin present in the blood.
Answer: False

 

Chapter 8 The Human Body Blood Match the Column

 

Answer: 1-C-4,2-D-3,3-B-2,4-A-1

 

Chapter 8 The Human Body Blood Answer In Words Or A Sentence

Question 1. Where in our body, blood cells are produced?
Answer: From bone marrow.

Question 2. Which organ pumps blood in our body?
Answer: Heart.

Question 3. Which of our blood cells is non-nucleated?
Answer: RBC or Erythrocytes.

Question 4. What are granulocytes?
Answer: These are WBC with granular cytoplasm.

Question 5. What are the types of lymphocytes?
Answer: Lymphocytes are of two types – B and T lymphocytes.

Question 6. State the function of platelets.
Answer: To help blood clotting.

 

Chapter 8 The Human Body Blood Short Answer Type Questions

Question 1. What are RBCs?
Answer: Red blood cells (RBCs), also called erythrocytes, are the most common type of blood cell and are the principal means of delivering oxygen (O2) to the body tissues- via blood flow through the circulatory system.

Question 2. What are WBCs?
Answer: White blood cells (WBCs), also called leucocytes, are the cells of the blood that are involved in protecting the body against infectious diseases caused by foreign invaders.

Question 3. What are monocytes?
Answer: Monocytes are white blood cells that fight infection by surrounding and destroying bacteria and viruses.

Question 4. What is blood plasma?
Answer: Blood plasma is the pale straw (yellow) colored liquid component of blood that normally holds the blood cells in whole blood in suspension; this makes plasma the extracellular matrix of blood cells.

It makes up about 55% of the body’s total blood volume.

Question 5. What is anemia?
Answer: The most common condition affecting the red blood cells of teens is anemia, a lower-than-normal number of red cells in the blood.

Anaemia is accompanied by a decrease in the amount of hemoglobin present in the blood.

 

Chapter 8 The Human Body Blood Long Answer Type Questions

Question 1. Write about the components of blood.
Answer:

Components of blood:

It is not made in a kitchen, but blood has ingredients, just like a recipe. To make blood, your body needs to mix:

1. Red blood cells, which carry oxygen throughout the body,
2. White blood cells, which fight infections,
3. Platelets, which are cell fragments that help you stop bleeding if you get a cut, and
4. Plasma is a yellowish liquid that carries nutrients, hormones, and proteins throughout the body.
5. Your body does not go to the store to buy those ingredients. It makes them. Bone marrow, which is goopy stuff inside your bones, makes the red blood cells, the white blood cells, and the platelets.

Plasma is mostly water, which is absorbed from the intestine from what you drink and eat, with the liver supplying important proteins.

Put all these ingredients together and you have blood- an essential part of the circulatory system.

Thanks to your heart (which pumps blood) and your blood vessels through which blood travels throughout your body from your head to your toes. Let’s find out more about each ingredient.

1. Red blood cells (RBCs)

Red blood cells (also called erythrocytes) look like flattened basketballs. Most of the cells in the blood are red blood cells.

They carry around an important chemical called hemoglobin that gives blood its red color. Blood and breathing go hand in hand.

How? The hemoglobin in blood delivers oxygen, which you get from the air you breathe to all parts of your body. Without oxygen, your body couldn’t keep working and stay alive.

2. White blood cells (WBCs)

White blood cells (also called leukocytes) are bigger than red blood cells. There are usually not a whole lot of white blood cells floating around in your blood when you are healthy.

Once you get sick, your body makes some more to protect you. There are different types of white blood cells that do different things to keep you well.

 

 

 

Granulocytes:

Do you know how your skin gets a little red and swollen around a cut or scrape? That means the granulocytes are doing their jobs.

They have a lot to do with how your body cleans things up and helps wounds heal after an injury.

Granulocytes also help to prevent infection by surrounding and destroying things that aren’t supposed to be in your body and by killing germs.

Granulocytes may be of three different types-Neutrophil, Eosinophil, and Basophil.

Agranulocytes: These are of two types- Lymphocytes and Monocytes.

1. Lymphocytes:

There are two types of lymphocytes:

B cells and T cells. B cells help make special proteins called antibodies that recognize stuff that should not be in your body, like bacteria or a virus you get from a sick friend.

Antibodies are, very specific, and can recognize only a certain type of germ. Once the antibody finds it, it gets rid of the germ so it cannot hurt you.

The really cool part is that even after you are better, B cells can become memory cells that remember how to make the special antibody so that if the same germ infects you again, it can kill the germ even faster.

T cells also battle germs that invade the body, but instead of making antibodies, they work by making special chemicals that help to fight the infection.

2. Monocytes:

Monocytes are white blood cells that fight infection by surrounding and destroying bacteria and viruses.

3. Platelets:

Platelets, also called thrombocytes, are tiny round cell fractions that help to make sure you do not bleed too much once you get a cut or scrape.

Cuts and scrapes break blood vessels. If a platelet reaches a blood vessel that’s been broken open, it sends out a chemical signal that makes other nearby platelets to stick together inside the vessel.

After the platelets form this plug, they send out more chemical signals that attract clotting factors.

These clotting factors work together to make a web of tiny protein threads within which other blood cells too (RBCs and WBCs) are entangled.

The platelets and this web of protein together with other blood cells make a blood clot. The clot keeps your blood inside the vessel while the break in the blood vessel heals up.

 

 

4. Plasma:

Plasma is a yellowish liquid that is mostly. water. But it also carries important nutrients, hormones, and proteins throughout the body.

Nutrients are chemicals from the food you eat that gives your body energy and other things your body’s cells need to do their work and keep you healthy.

Many proteins in plasma are really important to your body, like the clotting factors that help you stop bleeding if you get a cut or a scrape.

Plasma also carries away cell wastes- chemicals that the cell doesn’t want anymore.

Nutrients, hormones, proteins, and waste are dissolved in the plasma-kind of like the cocoa mix that dissolves in a cup of hot water. What are marshmallows? The blood cells-they float in the plasma.

Question 2. Write about the lymphocytes.
Answer:

1. Lymphocytes:

There are two types of lymphocytes:

B cells and T cells. B cells help make special proteins called antibodies that recognize stuff that should not be in your body, like bacteria or a virus you get from a sick friend.

Antibodies are, very specific, and can recognize only a certain type of germ. Once the antibody finds it, it gets rid of the germ so it cannot hurt you.

The really cool part is that even after you are better, B cells can become memory cells that remember how to make the special antibody so that if the same germ infects you again, it can kill the germ even faster.

T cells also battle germs that invade the body, but instead of making antibodies, they work by making special chemicals that help to fight the infection.

2. Monocytes:

Monocytes are white blood cells that fight infection by surrounding and destroying bacteria and viruses.

Question 3. Write about the diseases of white blood cells.
Answer:

Components of blood:

It is not made in a kitchen, but blood has ingredients, just like a recipe. To make blood, your body needs to mix:

1. Red blood cells, which carry oxygen throughout the body,
2. White blood cells, which fight infections,
3. Platelets, which are cell fragments that help you stop bleeding if you get a cut, and
4. Plasma is a yellowish liquid that carries nutrients, hormones, and proteins throughout the body.
5. Your body does not go to the store to buy those ingredients. It makes them. Bone marrow, which is goopy stuff inside your bones, makes the red blood cells, the white blood cells, and the platelets.

Plasma is mostly water, which is absorbed from the intestine from what you drink and eat, with the liver supplying important proteins.

Put all these ingredients together and you have blood- an essential part of the circulatory system.

Thanks to your heart (which pumps blood) and your blood vessels through which blood travels throughout your body from your head to your toes. Let’s find out more about each ingredient.

1. Red blood cells (RBCs)

Red blood cells (also called erythrocytes) look like flattened basketballs. Most of the cells in the blood are red blood cells.

They carry around an important chemical called hemoglobin that gives blood its red color. Blood and breathing go hand in hand.

How? The hemoglobin in blood delivers oxygen, which you get from the air you breathe to all parts of your body. Without oxygen, your body couldn’t keep working and stay alive.

2. White blood cells (WBCs)

White blood cells (also called leukocytes) are bigger than red blood cells. There are usually not a whole lot of white blood cells floating around in your blood when you are healthy.

Once you get sick, your body makes some more to protect you. There are different types of white blood cells that do different things to keep you well.

 

 

 

Granulocytes:

Do you know how your skin gets a little red and swollen around a cut or scrape? That means the granulocytes are doing their jobs.

They have a lot to do with how your body cleans things up and helps wounds heal after an injury.

Granulocytes also help to prevent infection by surrounding and destroying things that aren’t supposed to be in your body and by killing germs.

Granulocytes may be of three different types-Neutrophil, Eosinophil, and Basophil.

Agranulocytes: These are of two types- Lymphocytes and Monocytes.

1. Lymphocytes:

There are two types of lymphocytes:

B cells and T cells. B cells help make special proteins called antibodies that recognize stuff that should not be in your body, like bacteria or a virus you get from a sick friend.

Antibodies are, very specific, and can recognize only a certain type of germ. Once the antibody finds it, it gets rid of the germ so it cannot hurt you.

The really cool part is that even after you are better, B cells can become memory cells that remember how to make the special antibody so that if the same germ infects you again, it can kill the germ even faster.

T cells also battle germs that invade the body, but instead of making antibodies, they work by making special chemicals that help to fight the infection.

2. Monocytes:

Monocytes are white blood cells that fight infection by surrounding and destroying bacteria and viruses.

3. Platelets:

Platelets, also called thrombocytes, are tiny round cell fractions that help to make sure you do not bleed too much once you get a cut or scrape.

Cuts and scrapes break blood vessels. If a platelet reaches a blood vessel that’s been broken open, it sends out a chemical signal that makes other nearby platelets to stick together inside the vessel.

After the platelets form this plug, they send out more chemical signals that attract clotting factors.

These clotting factors work together to make a web of tiny protein threads within which other blood cells too (RBCs and WBCs) are entangled.

The platelets and this web of protein together with other blood cells make a blood clot. The clot keeps your blood inside the vessel while the break in the blood vessel heals up.

 

 

4. Plasma:

Plasma is a yellowish liquid that is mostly. water. But it also carries important nutrients, hormones, and proteins throughout the body.

Nutrients are chemicals from the food you eat that gives your body energy and other things your body’s cells need to do their work and keep you healthy.

Many proteins in plasma are really important to your body, like the clotting factors that help you stop bleeding if you get a cut or a scrape.

Plasma also carries away cell wastes- chemicals that the cell doesn’t want anymore.

Nutrients, hormones, proteins, and waste are dissolved in the plasma-kind of like the cocoa mix that dissolves in a cup of hot water. What are marshmallows? The blood cells-they float in the plasma.

Blood Types:

Everybody’s blood is red, but it’s not all the same. There are eight blood types, described using the letters A, B, and O.

Those letters stand for certain proteins found in the red blood cells. Not everyone has the same proteins. In addition to getting a letter or two, a person’s blood is either “positive” or “negative”.

That doesn’t mean one person’s blood is good and another person’s blood is bad. It’s a way of keeping track of whether someone’s blood has a certain protein called Rh protein.

This protein is called “Rh” because scientists found it while studying Rhesus monkeys. If your blood is positive, you have this protein.

If it is negative, you do not. Either way is totally fine. Blood types are important if a person ever wants to donate blood or needs a blood transfusion. Getting blood of the wrong type can make a person sick.

The disease of the red blood cells:

The most common condition affecting the red blood cells of teens is anemia, a lower-than-normal number of red cells in the blood.

Anaemia is accompanied by a decrease in the amount of hemoglobin present in the blood.

Causes of anemia can be grouped into two categories anemia caused by insufficient RBC production and anemia caused by RBCs being destroyed too soon.

1. Diseases of platelets: 

1. Thrombocytopenia, or a lower-than-normal number of platelets, is usually diagnosed because a person has abnormal bruising or bleeding.

2. Diseases of the clotting system:

The body’s clotting system depends on platelets as well as many clotting factors and other blood components.

If a hereditary defect affects any of these components, a person can have a bleeding disorder.

Diseases of the white blood cells:

1. Neutropenia happens when there aren’t enough of certain types of white blood cells (neutrophils) to protect the body against bacterial infections.
2. Human Immunodeficiency Virus (HIV) is a virus that attacks certain types of WBCs (lymphocytes) that work to fight infection.
   Infection with the virus can result in AIDS (Acquired Immunodeficiency Syndrome), leaving the body prone to infections and certain other diseases.
3. Leukemias are cancers of the cells that produce WBCs.

Different types of WBCs defend the human body against the attack of micro-organisms. They collect at the site of infection and engulf the invaders.

WBC also manufacture antibodies that provide immunity to the body. Every day various microbes invade and enter the human body.

There are certain mechanisms through which these microbes are destroyed once they enter our bodies. The mechanism acts through discharge.

The flow of fluid from part of the body such as from the nose is called a discharge.

 

Question 4. Write about the major functions of blood.
Answer:

Functions of blood:

1. Transport of nutrients, hormones, and enzymes to various parts of the body.
2. Transport of respiratory gases and waste products.
3. Protection against microbes
4. Maintenance of water balance and acid-base balance.
5.  Antibody formation.

 

Chapter 8 The Human Body Lungs Review Questions Environment Review Questions MCQ

Question 1. Lungs are a part of __________ system.

1. Circulatory
2. Respiratory
3. Digestive
4. Nervous

Answer: 2. Respiratory

Question 2. Beneath the lungs is the

1. Heart
2. Stomach
3. Lungs
4. Trachea

Answer: 3. Lungs

Question 3. Lungs help us in

1. Bronchi
2. Talking
3. Lungs
4. Breathing

Answer: 4. Breathing

Question 4. During inhalation the diaphragm

1. Relax
2. Contract
3. Plays no role
4. Undulates

Answer: 2. Contract

Question 5. Bronchioles end in

1. Alveoli
2. Lungs
3. Trachea
4. Capillaries

Answer: 1. Alveoli

Question 6. Capillaries are small

1. Blood vessels
2. Trachea
3. Arteries
4. Veins

Answer: 1. Blood vessels

Question 7. Tiny hairs called cilia move gently to keep mucus and dirt out of the

1. Heart
2. Blood
3. Lungs
4. Air

Answer: 3. Lungs

Question 8. The ultimate branches of the trachea are

1. Bronchi
2. Alveoli
3. Lings
4. Bronchioles

Answer: 4. Bronchioles

Question 9. Lungs are covered by

1. Air
2. Blood
3. Mucus
4. Pleural membranes

Answer: 4. Pleural membranes

Question 10. Larynx is

1. Brainbox
2. Voice box
3. Membranous
4. Tracheal

Answer: 2. Voicebox

Question 11. Asthma is a problem of _________ system.

1. Respiratory
2. Circulatory
3. Lungs
4. Tracheal

Answer: 1. Respiratory

 

Chapter 8 The Human Body Lungs Fill In The Blanks

Question 1. Lungs work as a part of our _________ system.
Answer: Respiratory

Question 2. Lungs are located inside _________.
Answer: Chest

Question 3. At the end of each bronchiole is a special air sac called _________.
Answer: Chest

Question 4. Beneath the lungs is the _________ a dome-shaped muscle.
Answer: Diaphragm

Question 5. Lungs are covered by _________ membranes.
Answer: Qleural

Question 6. Our voice is produced from _________
Answer: Larynx

Question 7. Illnesses like bronchitis and _________ hard for air to get into the alveoli.
Answer: Pneumonia

 

Chapter 8 The Human Body Lungs Identify As True Or False

Question 1. Breathing air is necessary for keeping us alive.
Answer: True

Question 2. Lungs are protected by the heart.
Answer: False

Question 3. Above the lungs is the diaphragm.
Answer: False

Question 4. The trachea divides into bronchioles.
Answer: False

Question 5. Each alveolus has a mesh-like covering of very small blood vessels called capillaries.
Answer: True

Question 6. As we inhale or breathe in, our diaphragm contracts and flattens out.
Answer: True

Question 7. During exhalation, the diaphragm relaxes and moves down.
Answer: False

Question 8. Our voice box is called the larynx.
Answer: True

Question 9. Exhalation is bad for the lungs.
Answer: False

Question 10. Asthma is a neurological problem.
Answer: False

 

Chapter 8 The Human Body Lungs Match the Column

 

Answer: A-2,B-4,C-1,D-5

 

Chapter 8 The Human Body Lungs Answer In Word Or A Sentence

Question 1. Name the principal organ of respiration.
Answer: Lungs.

Question 2. How many pairs of ribs form the rib cage?
Answer: 12 pairs.

Question 3. Name the dome-shaped structure located beneath the lungs.
Answer: Diaphragm.

Question 4. What is the name of the respiratory windpipe?
Answer: Trachea.

Question 5. What is the name of the air sacs situated in our lungs?
Answer: Alveoli.

Question 6. Name the organ responsible for talking.
Answer: Larynx.

Question 7. Name any two respiratory problems.
Answer: Asthma/Bronchitis / Pneumonia (any two to be mentioned).

Question 8. Find out the odd one: bronchus, alveoli, artery, nasal passage.
Answer: Artery.

 

Chapter 8 The Human Body Lungs Short Answer Type Questions

Question 1. What are lungs?
Answer: Lungs are the pair of organs situated within the ribcage, consisting of elastic sacs with branching passages into which air is drawn so that oxygen can pass into the blood and carbon dioxide be removed.

Question 2. What is a trachea?
Answer: The trachea, colloquially called the windpipe, is a tube that connects the pharynx and larynx to the lungs, allowing the passage of air.

Question 3. What are pulmonary alveoli?
Answer: The pulmonary alveoli are the terminal ends of the respiratory tree which are sites of gas exchange with the blood.

Question 4. What is the diaphragm?
Answer: It is a dome-shaped muscular partition separating the thorax from the abdomen in mammals.

It plays a major role in breathing, as its contraction increases the volume of the thorax and so inflates the lungs.

Question 5. What is asthma?
Answer: Asthma is a chronic (long-term) lung disease that inflames and narrows the airways.

Asthma causes recurring periods of wheezing (a whistling sound when you breathe), chest tightness, shortness of breath, and coughing.

Question 6. Fill up the gap: Environment→ 1 → Pharynx and larynx →2→ bronchi→ 3→ 4
Answer:

1. Nostrils
2. trachea
3.  bronchioles
4. alveoli

 

Chapter 8 The Human Body Lungs Long Answer Type Questions

Question 1. Describe the location and structure of the lungs.
Answer:

Location of lungs :

Your lungs are in your chest, and they are so large that they take up most of the space there. You have two lungs, but they aren’t of the same size as your eyes or nostrils.

Instead, the lung on the left side of your body is a bit smaller than the lung on the right. This extra space on the left leaves room for your heart.

Your lungs are protected by your rib cage, which is made up of 12 sets of ribs.

These ribs are connected to your spine in your back and go around your lungs to keep them safe.

Beneath the lungs is the diaphragm, a dome-shaped muscle that works with your lungs to allow you to inhale (breathe in) and exhale (breathe out) air.

You can’t see your lungs, but it’s easy to feel them in action: Put your hands on your chest and breathe in very deeply. You will feel your chest getting slightly bigger.

Now breathe out the air, and feel your chest returning to its regular size.

Structure of lungs :

From the outside, the lungs are pink and a bit squishy, like a sponge. At the bottom of the trachea, or windpipe, there are two large tubes.

These tubes are called the main stem bronchi, and one heads left into the left lung, while the other heads right into the right lung.

Each main stem bronchus is the name for just one of the bronchi-then branches off into tubes, or bronchi, which get smaller and even smaller still, like branches on a big tree.

The tiniest tubes are called bronchioles, and there are about 30,000 of them in each lung. Each bronchiole is about the same thickness as a hair.

At the end of each bronchiole is a special area, that leads into clumps of tiny air sacs called alveoli.

There are about 600 million alveoli in our lungs and if we stretch them out, they would cover an entire tennis court.

Each alveolus-what we call just one of the alveoli- has a mesh-like covering of very small blood vessels called capillaries.

These capillaries are so tiny that the cells in your blood need to line up a single file just to march through them.

 

 

Question 2. Write the mechanism of breathing.
Answer:

Functioning of lungs:

When you are walking with your pet, cleaning your room, or playing football, you probably do not think about inhaling (breathing in)-you have got other things on your mind.

But every time you inhale air, dozens of body parts work together to help get that air in there without you ever thinking about it.

As you inhale or breathe in, your diaphragm contracts and flattens out. This allows it to move down, so your lungs have more room to grow larger as they fill up with air.

“Move over, diaphragm, I’m filling up!” is what your lungs would say. And the diaphragm is not the only part that gives your lungs the room they need.

Your rib muscles also lift the ribs up and outward to give the lungs more space. At the same time, you inhale air through your mouth and nose, and the air heads down your trachea or windpipe.

On the way down the windpipe, tiny hairs called cilia move gently to keep mucus and dirt out of the lungs.

The air then goes through the series of branches in your lungs, through the bronchi and the bronchioles.

The air finally ends up in the 600 million alveoli. As these millions of alveoli get filled up with air, the lungs get bigger. It’s the alveoli that allow oxygen from the air to pass into your blood.

All the cells in the body need oxygen every minute of the day. Oxygen passes through the walls of each alveolus into the tiny capillaries that surround it.

The oxygen enters the blood in the tiny capillaries, hitching a ride on red blood cells and traveling through layers of blood vessels to the heart.

The heart then sends the oxygenated (filled with oxygen) blood out to all the cells in the body.

When it’s to exhale (breathe out), everything happens in reverse. Now it’s the diaphragm’s turn to say, “Move it!” Your diaphragm relaxes and moves up, pushing air out of the lungs.

Your rib muscles become relaxed and your ribs move in again, creating a smaller space in your chest.

By now your cells have used the oxygen they need, and your blood is carrying carbon dioxide and other wastes that must leave your body.

The blood comes back through the capillaries and the wastes enter the alveoli.

Then you breathe them out in the reverse order of how they came in the air goes through the bronchioles, out the bronchi, out the trachea, and finally out through your mouth and nose.

 

 

The air that you breathe out not only contains waste and carbon dioxide, but it’s warm too art balls and to me Sequence As air travels through your body, it picks up heat along the way.

You can feel this heat by putting your hand in front of your mouth or nose as you breathe out. With all this movement, you might be wondering why things don’t get stuck as the lungs fill and empty.

Luckily, your lungs are covered by two really slick special layers called pleural membranes.

These membranes are separated by a fluid that allows them to slide around easily while you inhale and exhale.

 

Question 3. How lungs can be taken care of?
Answer:

Your lungs are important for breathing and also for talking. Above the trachea (windpipe) is the larynx, which is sometimes called the voice box.

Across the voice box are two tiny ridges called vocal cords, which open and close to make sounds. When you exhale air from the lungs, it comes through the trachea and larynx and reaches the vocal cords.

If the vocal cords are closed and the air flows between them, the vocal cords vibrate and a sound is made.

The amount of air you blow out from your lungs determines how loud a sound will be and how long you can make the sound.

Very deeply and saying the names of all the kids in your class-how far can you get without taking the next breath? The next time you’re outside.

Try shouting and see what happens- shouting requires lots of air, so you’ll need to breathe in more frequently than you would if you were only saying the words.

Take care of your lungs :

1. Do not smoke and keep away from others who smoke. Lungs do not like cigarette smoke, it can damage them, and cause disease and even death.
   Stay out of the workshop if someone is using chemicals, as some chemicals can damage your lungs.
2. Remind mother, she should wear a mask and have windows open if she is using some chemicals when she is cleaning the oven or using drain cleaner.
3. Get plenty of exercise. It makes the muscles around your lungs work harder and makes them stronger.

Problems of lungs:

Some people have asthma. Sometimes when they get a cold, are in contact with something they are allergic to, or exercise hard, the tiny tubes in their lungs get tighter and there is a lot more mucus.

This makes it hard to get air into the alveoli. They can become very short of breath and need medication to help their lung work well.

Illnesses like bronchitis and pneumonia also make it hard for air to get into the alveoli.

When the lungs do not work well, that means there is not enough oxygen getting around to all the cells of the body, and the body systems do not work as well as usual and you feel short of breath.

People affected with Tuberculosis spit blood while coughing, and suffer from mild fever (especially at night), respiratory trouble, and chest pain.

Severe weakness is felt and loss of body weight takes place rapidly.

Question 4. Write about the common respiratory
Answer:

Problems of lungs:

Some people have asthma. Sometimes when they get a cold, are in contact with something they are allergic to, or exercise hard, the tiny tubes in their lungs get tighter and there is a lot more mucus.

This makes it hard to get air into the alveoli. They can become very short of breath and need medication to help their lung work well.

Illnesses like bronchitis and pneumonia also make it hard for air to get into the alveoli.

When the lungs do not work well, that means there is not enough oxygen getting around to all the cells of the body, and the body systems do not work as well as usual and you feel short of breath.

People affected with Tuberculosis spit blood while coughing, and suffer from mild fever (especially at night), respiratory trouble, and chest pain.

Severe weakness is felt and loss of body weight takes place rapidly.

 

Chapter 8 The Human Body Bones Bone-Joints And Muscles Review Questions Environment Review Questions MCQ

Question 1. Bones are the parts of

1. Skeletal system
2. Locomotory system
3. Movable system
4. Joints

Answer: 1. Skeletal system

Question 2. Our ribs protect the

1. Heart
2. Lungs
3. Both ‘a’ and ‘b’ correct
4. Kidneys

Answer: 3. Both ‘a’ and ‘b’ correct

Question 3. The number of bones in the adult human body is

1. 200
2. 206
3. 300
4. Variable

Answer: 2. 206

Question 4. Bones are largely made of

1. Calcium
2. Iron
3. Zinc
4. Minerals

Answer: 1. Calcium

Question 5. The outside part of the bone is called the

1. Involuntary
2. Voluntary
3. Cancellous
4. Periosteum

Answer: 4. Periosteum

Question 6. The skull is like a natural helmet that protects the

1. Eyes
2. Ears
3. Brain
4. Face

Answer: 3. Brain

Question 7. The number of cervical vertebrae is

1. 5
2. 7
3. 10
4. 12

Answer: 2. 7

Question 8. The last 2 pairs of ribs are called the

1. Floating ribs
2. Flying ribs
3. True ribs
4. False ribs

Answer: 1. Floating ribs

Question 9. The bone between our shoulder and the elbow is

1. Femur
2. Humerus
3. Collar bone
4. Coccyx

Answer: 2. Humerus

Question 10. The study of joints is called

1. Biology
2. Anthology
3. Arthrology
4. Astrology

Answer: 3. Arthrology

Question 11. Synovial joints are

1. Movable
2. Contain fluid
3. Fixed
4. Both ‘a’ and ‘b’ correct

Answer: 4. Both ‘a’ and ‘b’ correct

Question 12. The elbow is an example of

1. Hinge joint
2. Saddle joint
3. Condyloid joint
4. Ball and socket joint

Answer: 1. Hinge joint

Question 13. Smooth muscles are

1. Involuntary
2. Voluntary
3. Cardiac
4. Skeletal

Answer: 1. Involuntary

Question 14. The muscle that makes up the heart is called

1. Smooth muscle
2. Visceral muscle
3. Cardiac muscle
4. Skeletal muscle

Answer: 3. Cardiac muscle

Question 15. Muscles get most of their energy from

1. Food
2. Blood
3. Joints
4. Glucose

Answer: 4. Glucose

Question 16. Immovable joints can be seen in

1. knee
2. thumbs
3. skull
4. shoulder

Answer: 3. skull

Question 17. A partly movable joint can be found in

1. skull
2. wrist
3. sternum
4. shoulder

Answer: 3. sternum

Question 18. The number of bones in a newborn baby is

1. 206
2. 300
3. 500
4. nil

Answer: 2. 300

 

Chapter 8 The Human Body Bones Bone-Joints And Muscles Fill In The Blanks

Question 1. Muscles connect the to __________ the bones.
Answer: Joints

Question 2. __________ make up the framework of our bodies.
Answer: Bones

Question 3. The adult human body has __________ bones.
Answer: 206

Question 4. The center of the bone, or __________ is where your blood is created.
Answer: Marrow

Question 5 The outside part of the bone is called the __________.
Answer: Periosteum

Question 6. The __________ make a shield around our lungs and heart.
Answer: Ribs

Question 7. There are __________ pairs of ribs in the human body.
Answer: 12

Question 8. The arm has 3 bones-the humerus, the radius, and the __________
Answer: Ulna

Question 9. The __________ is the largest bone in our body.
Answer: Femur

Question 10. __________ is a degenerative joint disease that middle-aged and older adults experience.
Answer: Osteoarthritis

Question 11. The study of joints is called __________
Answer: Arthrology

Question 12. Synovial joints have __________ to prevent excessive movement.
Answer: Ligaments

Question 13 A __________ joint can move in the axis at a right angle to the joints involved.
Answer: Hinge

Question 14. Ball and socket joints are perhaps the most versatile __________ joints.
Answer: Synovial

Question 15. We have three different types of muscles smooth Muscle, __________ muscle, and skeletal muscle
Answer: Cardiac

Question 16. Skeletal muscles are held to the bones with the help of __________
Answer: Tendons

Question 17. Muscles work by __________ and contracting.
Answer: Expanding

Question 18. Muscles get most of their energy from __________.
Answer: Glucose

 

Chapter 8 The Human Body Bones Bone-Joints And Muscles Identify As True Or False

Question 1. The bones that make up our skeletal system provide shape and protection.
Answer: True

Question 2. Wherever two bones meet, there is a blood vessel to hold them together and allow them to move.
Answer: False

Question 3. Bones are living, growing, and changing parts of our bodies.
Answer: True

Question 4. Bones are largely made of calcium and other minerals.
Answer: True

Question 5. The spine has 26 bones which are like circles with wings on the sides and back.
Answer: True

Question 6. We have 7 thoracic vertebrae.
Answer: False

Question 7. At the front of the body, the top 7 ribs are attached to the sternum.
Answer: True

Question 8. The femur is the bone between your shoulder and the elbow.
Answer: False

Question 9. Asthma is a rheumatic disease that has symptoms of pain and limited movement.
Answer: False

Question 10. Joints are places where bones meet.
Answer: True

Question 11. In the skull, the synovial joints are called sutures.
Answer: False

Question 12. Hinge joints only allow rotation.
Answer: False

Question 13. Joints form the connections between ligaments.
Answer: False

Question 14. Smooth muscles are sometimes also called involuntary muscles.
Answer: True

Question 15. The muscle that makes up the heart is called cardiac muscle.
Answer: True

Question 16. Muscles have long, thin cells that are grouped into bundles.
Answer: True

Question 17. When you exercise a lot, your muscles get refreshed.
Answer: False

 

Chapter 8 The Human Body Bones Bone-Joints And Muscles match The Columns

 

Answer: A-5,B-1,C-2,D-4

 

Answer: A-2,B-4,C-5,D-1

 

Answer: A-3,B-4,C-2D-5

 

Chapter 8 The Human Body Bones Bone-Joints And Muscles Answer In Words Or A Sentence

Question 1. How many bones are there in the adult human body?
Answer: Adults have 206 bones.

Question 2. Name the outer layer of a bone
Answer: Periosteum.

Question 3. Where is bone marrow located?
Answer: In the inner cavity of long bones.

Question 4. Where is our brain enclosed?
Answer: Inside the skull.

Question 5. Name two organs enclosed within ribs.
Answer: Heart and lungs.

Question 6. How many cervical vertebrae are there in the human body?
Answer: They are 7 in number.

Question 7. How many floating ribs are there in our body?
Answer: Two.

Question 8. Name the bone forming the shoulder blade.
Answer: Scapula.

Question 9. Name the bone between your shoulder and the elbow.
Answer: Humerus.

Question 10. How many bones are there in each hand of
ours?
Answer: 19

Question 11. Name the largest bone in our body.
Answer: Femur.

Question 12. Name the two long bones below the knee.
Answer: Tibia and fibula.

Question 13. What is arthrology?
Answer: It is the study of joints.

Question 14. Give an example of the hinge joint.
Answer: Elbow joint.

Question 15. Give an example of a saddle joint.
Answer: Thumb joint.

Question 16. What type of joint is the shoulder joint?
Answer: Ball and socket joint.

Question 17. How many types of muscles are there in our body?
Answer: Three types.

Question 18. What type of muscle is found in our intestine?
Answer: Smooth muscles.

Question 19. Name the structure joining bone and skeletal muscle.
Answer: Tendon.

Question 20. What is myocardium?
Answer: It is the bulk of the heart muscle.

 

Chapter 8 The Human Body Bones Bone-Joints And Muscles Short Answer SA Type Questions

Question 1. What are bones? State their functions.
Answer: A bone is a rigid organ that constitutes part of the vertebrate skeleton.

Bones give mechanical support to the body and protect the various organs of the body, produce red and Answer: white blood cells, store minerals, and also enable mobility.

Question 2. What are bone joints?
Answer: A joint or articulation (or articular surface) is the location at which bones connect.

They are constructed to allow movement (except for skull, sacral, sternal, and pelvic bones) and provide mechanical support, and are classified structurally and functionally.

Question 3. How many bones are there in the human body? Babies skeletons are made up of more than 300 Answer: parts, but by the time we become adults we only have 206 bones.

It is just that some of our baby bones are made, partly or completely, of cartilage. As we grow bigger and heavier, cartilage is slowly replaced by harder bone.

Some smaller bones join together to make one bigger bone.

Question 4. State the functions of the skull and spine (vertebral column).
Answer:

1. The skull is like a natural helmet that protects the brain.
2. The spine protects the nerves in the spinal column.

Question 5. What are the first two regions of our vertebral column?
Answer:

1. The top 7 are called the cervical vertebrae and they support your head and neck.
2. The next 12 are called the thoracic vertebrae. These hold one end of your ribs.

Question 6. Which regions of our vertebral column have fused vertebrae?
Answer:

1. The sacrum is a large bone that is actually made of 5 vertebrae fused (joined) together.
2. At the bottom of the spine is the coccyx, which is one bone made of 4 small vertebrae fused together.

Question 7. What are true ribs?
Answer: The first seven ribs attached to the sternum (the breast bone) in the front are known as true ribs (or sternal ribs).

Question 8. What are false ribs and floating ribs?
Answer: The lower five ribs do not directly connect to the sternum and are known as false ribs.

The upper three false ribs connect to the costal cartilages of the ribs just above them.

The last two false ribs, however, usually have no ventral attachment (no anchor at all in front) and are called floating, fluctuating or vertebral ribs.

Question 9. What is arthritis?
Answer: Arthritis is a form of joint disorder that involves inflammation in one or more joints. There are several different forms of arthritis.

The most common form of arthritis is osteoarthritis, a result of trauma to the joint, infection of the joint, or age.

Question 10. How many types of joints are there in the human body?
Answer: There are three main types of joints; Fibrous (immovable), cartilaginous (partially movable), and synovial (freely movable) joints.

Question 11. What are the functions of joints?
Answer: Joints are functional junctions between two or more bones. Joints bind the skeleton together to give structure and allow muscles to move bones to perform certain tasks such as running, reaching, and grasping.

Question 12. What are fibrous joints?
Answer: These joints have no joint cavity and are connected via fibrous connective tissue. The skull bones are connected by fibrous joints.

Sutures are found between the bones of the skull. In fetal skulls, the sutures are wide to allow slight movement during birth.

Question 13. What are synovial joints?
Answer: These are bone joints characterized by the presence of synovial fluid within a space that encapsulates the articulating surface (surfaces that touch each other) of the joint.

The synovial capsule reduces the friction between the bones allowing more smooth movement.

Question 14. What are ball and socket joints?
Answer: These are a type of synovial bone joint. They are multiaxial joints, which means they can move in many axes. One bone has a ball and the other one has a socket.

Question 15. What are smooth muscles?
Answer: Smooth muscle is an involuntary, non-striated muscle. Smooth muscles are usually in sheets or layers, with one layer of muscle behind the other.

We can’t control this type of muscle. Our brain and body tell these muscles what to do without you even thinking about it. Examples-muscles of the stomach.

Question 16. What is myocardium?
Answer: The myocardium is the muscular wall of the heart or the heart muscle. It contracts to pump blood out of the heart and then relaxes as the heart refills with returning blood.

Question 17. What is a tendon?
Answer: A tendon is a tough band of fibrous connective tissue that usually connects muscle to bone and is capable of withstanding tension. Tendons are similar to ligaments.

Question 18. Mention two differences between bones and muscles.
Answer: 1. Bones are hard and composed of osteocytes. Muscles are made of contractile tissue.
2. Bones form the skeleton of the body. Muscles keep the bones in place and play a significant role in their movement.

 

Chapter 8 The Human Body Bones Bone-Joints And Muscles Long Answer Type Questions

Question 1. Write about the parts of bones.
Answer:

The cartilage, muscles, ligaments, and tendons, all work as one, holding bones together and letting joints move. Muscles connect the joints to the bones.

Flexing of the muscles and the ability to bend at the joints moves the bones to accomplish skilled body motions.

1. Bones

Bones make up the framework of our bodies. We call this framework the skeleton. Bones are living, growing, and changing parts of our bodies.

Baby skeletons are made up of more than 300 parts, but by the time we become adults we only have 206 bones. No, we don’t lose any.

It’s just that some of our baby bones are made, partly or completely, of cartilage. As we grow bigger and heavier, cartilage is slowly replaced by harder bone.

Some smaller bones are joined together to make one bigger bone.

Bones are largely made of calcium and other minerals. They are hard enough to support our weight and daily stress. Bones protect our major organs and give our bodies shape.

Bones are actually living tissue. The center of the bone, or marrow, is where your blood is created.

Parts of bones:  Most bones have 4 parts:

1. The outside part of the bone is called the periosteum. This is a thin but very dense layer that has the nerves and blood vessels which nourish the bone.
2.  Compact bone is next. It is smooth and very hard.
3. Cancellous bone comes next and this looks a bit like a sponge but is much stronger.
4. On the very inside of many bones is the bone marrow. It looks a bit like a jelly and it makes new blood cells for the body.

Functions of bones:

1. The bones of the skeleton give us our shape and our posture. Without our spine (backbone) and leg bones, we would be unable to stand erect. Bones also protect the softer parts of our bodies.
2. The skull is like a natural helmet that protects the brain.
3. The spine protects the nerves in the spinal column.
4. The rib makes a shield around our lungs and heart.
5. They act as a base for muscles, ligaments, and tendons. Ligaments connect bones to bones and tendons connect muscles to bones.
6. They all work together to help us move around.

 

 

Different major bony parts of our body

1. Some bones protect the brain. You can feel the bone at the back of your head and forehead.
2. Some bones make the framework for your face. You can feel the bones around your eyes.
3. Some bones in the middle part of your ear carry sound from your eardrum to the inner De ear.
4. You can feel the jawbone under your chin and where it hinges just under your ear. It is the only bone in your skull that you can move.

2. Spine (Vertebral Column)

The spine has 26 bones which are like circles with wings on the sides and back. They are called vertebrae. There are small discs made of cartilage between each vertebra.

They act like shock absorbers and stop the bones from rubbing against each other. There is also a hole through each of the vertebrae where the spinal cord goes.

 

1. The top 7 are called the cervical vertebrae and they support your head and neck.
2. The next 12 are called the thoracic vertebrae. These hold one end of your ribs.
3. The next 5 are the lumber vertebrae.
4. The next, the sacrum, is a large bone that is actually made of 5 vertebrae fused (joined) together.
5. At the bottom of the spine is the coccyx, which is one bone made of 4 small vertebrae fused together.

 

 

3. Ribs

Ribs make a protective cage around your lungs and heart. There are usually 12 pairs of ribs, each pair attached to the spine at the back.

Each rib is attached to the ribs above and below it by muscles and ligaments.

1. At the front of the body, the top 7 ribs are attached to the sternum (or breast bone).
2. The next 3 pairs are joined to the ribs above and to the sternum, by cartilage.
3. The last 2 pairs of ribs are called the ‘floating’ ribs. They are called floating because they are attached only to the vertebrae and not to the sternum. They don’t have sharp edges sticking out.

4. Arms

Each arm is fastened to the scapula (the shoulder blade) at the back, (which is a triangle-shaped bone near the top of the ribs) and to the clavicle at the front (the collar bone).

The arm has 3 bones-the humerus, the radius, and the ulna. The humerus is the bone between your shoulder and the elbow.

The radius and ulna bones go from the elbow to the wrist. At the end of the radius and ulna is your wrist. Your wrist has 8 small bones, so it is really flexible. In each hand, there are 19 bones.

5. Legs

Your legs are fastened to your pelvis at the hips. The pelvis is shaped like a bowl and supports the contents of your tummy.

1. Legs need to be large and strong to support something to pull them. This job is done by the rest of the body.
2. The femur is the largest bone in the body and it goes from the pelvis to the knee.
3. Another bone called the patella, or kneecap covers the knee joint to protect it.
4. Below the knee, there are 2 bones. These are the tibia and the fibula. They join up to a large bone in the ankle called the talus.
5. There are 6 other bones here so you can move your ankle around but you cannot move it as much as you can move your wrist. Your feet and ankles have a total of 52 bones in them.

 

 

Question 2. Write about the functions of bones.
Answer:

What are the functions of your joints:

Aside from smooth movement, joints also have other functions. They allow you to grow. When your brain grows, the sutures in your skull accommodate.

The primary cartilaginous joints of your knees and elbows allow you to grow to your full height. Joints also serve to minimize friction and cushion the bones against impact.

Joints are very important areas in your body. They give you space for growth and allow you to move the way you want.

What are the classifications of joints:

Joints can be classified according to what material unites the bones. The three main types of joints are fibrous joints, cartilaginous joints, and synovial joints.

Fibrous joints are joined by fibrous tissue cartilaginous joints are united by cartilage or a mix of cartilage and fibrous tissue; synovial joints are connected by a synovial membrane that surrounds the joint cavity.

1. Fibrous joints:

The movement allowed by these joints is dependent on the length of the fibrous tissue connecting the bones. In the skull, these joints are called sutures.

Sutures are connected by strong connective tissues and allow very little or no movement in adults. These are known as immovable joints.

 

 

2. Cartilaginous joints:

These joints can be primary cartilaginous joints and secondary cartilaginous joints. Primary cartilaginous joints are connected by cartilage temporarily, early in life.

An example is your knee joint. Later on, the cartilage becomes bone. Secondary cartilaginous joints. consist of bones with the ends covered by cartilage and connected with fibrous. tissue.

These joints are found in the vertebral column and allow slight movement. These are known as partly movable joints.

3. Synovial joints:

These joints are present in the shoulder, hip, knee, ankle, toes, elbow, and the joints of the limbs including the loot fingers.

Their name is derived from the fact sling that they have synovial fluid and is du enclosed within a synovial capsule.

joints allow considerable movement but have ligaments to prevent excessive movement. These are known as movable lee joints.

What are the types of synovial joints?

Synovial joints can be categorized into six types based on the movement they allow. The first type, a plane joint, allows gliding or sliding movement, and the bones involved usually have flat surfaces.

An example of a plane joint is found in the shoulder, between the shoulder blade (acromion of the scapula) and the clavicle.

A hinge joint can move in the axis at a right angle to the joints involved. An example is the elbow joint, which connects the humerus and the ulna.

The movement allowed by this joint includes flexion (bending) and extension (straightening) of your elbow.
The third type of synovial joint is the condyloid joint.

In Greek, “condyloid” means knuckle-like. This type of joint allows movement in two axes. Therefore you can bend it, straighten it, move it from side to side, and rotate it.

An example is your wrist joint. song yen send scrawled The fourth synovial joint type is the saddle joint.

 

 

This joint is so-named because the opposing surfaces of the involved bones look like a saddle-one has a convex surface, while the other has a concave surface.

The thumb joint, which can also move in two axes, is a good example of this joint.

Ball and socket joints are perhaps the most versatile synovial joints. They are multi-axial joints, which means they can move in many axes. One joint has a ball and the other joint has a socket.

The shoulder joint and the hip joints are examples of this type. In the hip joint, the ball is the head of the leg bone (femur) while the socket is the acetabulum of the hip (pelvis).

Try to experiment with the kinds of movement you can make with your hip joint. You can bend, flex, open, close, rotate and circularly move your legs.

These movements of the hip joint are very important for ballerinas and dancers who have complex leg routines.

The last type of synovial joint is the pivot joint. These joints only allow rotation. One bone serves like a ring while the other bone has a rounded process rotating within the ring.

This type is found in your neck, particularly in your first two cervical bones called the atlas (the ring) and the dens (the rounded process). This allows you to rotate your head.

 

Question 3. Write about different types of ribs of our body.
Answer:

3. Ribs

Ribs make a protective cage around your lungs and heart. There are usually 12 pairs of ribs, each pair attached to the spine at the back.

Each rib is attached to the ribs above and below it by muscles and ligaments.

1. At the front of the body, the top 7 ribs are attached to the sternum (or breast bone).
2. The next 3 pairs are joined to the ribs above and to the sternum, by cartilage.
3. The last 2 pairs of ribs are called the ‘floating’ ribs. They are called floating because they are attached only to the vertebrae and not to the sternum. They don’t have sharp edges sticking out.

4. Arms

Each arm is fastened to the scapula (the shoulder blade) at the back, (which is a triangle-shaped bone near the top of the ribs) and to the clavicle at the front (the collar bone).

The arm has 3 bones-the humerus, the radius, and the ulna. The humerus is the bone between your shoulder and the elbow.

The radius and ulna bones go from the elbow to the wrist. At the end of the radius and ulna is your wrist. Your wrist has 8 small bones, so it is really flexible. In each hand, there are 19 bones.

5. Legs

Your legs are fastened to your pelvis at the hips. The pelvis is shaped like a bowl and supports the contents of your tummy.

1. Legs need to be large and strong to support something to pull them. This job is done by the rest of the body.
2. The femur is the largest bone in the body and it goes from the pelvis to the knee.
3. Another bone called the patella, or kneecap covers the knee joint to protect it.
4. Below the knee, there are 2 bones. These are the tibia and the fibula. They join up to a large bone in the ankle called the talus.
5. There are 6 other bones here so you can move your ankle around but you cannot move it as much as you can move your wrist. Your feet and ankles have a total of 52 bones in them.

 

Question 4. What are the components of our vertebral column?
Answer:

2. Spine (Vertebral Column)

The spine has 26 bones which are like circles with wings on the sides and back. They are called vertebrae. There are small discs made of cartilage between each vertebra.

They act like shock absorbers and stop the bones from rubbing against each other. There is also a hole through each of the vertebrae where the spinal cord goes.

1. The top 7 are called the cervical vertebrae and they support your head and neck.
2. The next 12 are called the thoracic vertebrae. These hold one end of your ribs.
3. The next 5 are the lumber vertebrae.
4. The next, the sacrum, is a large bone that is actually made of 5 vertebrae fused (joined) together.
5. At the bottom of the spine is the coccyx, which is one bone made of 4 small vertebrae fused together.

 

 

Question 5. Describe the bony components of our legs.
Answer:

Legs

Your legs are fastened to your pelvis at the hips. The pelvis is shaped like a bowl and supports the contents of your tummy.

1. Legs need to be large and strong to support something to pull them. This job is done by the rest of the body.
2. The femur is the largest bone in the body and it goes from the pelvis to the knee.
3. Another bone called the patella, or kneecap covers the knee joint to protect it.
4. Below the knee, there are 2 bones. These are the tibia and the fibula. They join up to a large bone in the ankle called the talus.
5. There are 6 other bones here so you can move your ankle around but you cannot move it as much as you can move your wrist. Your feet and ankles have a total of 52 bones in them.

 

 

Question 6. Write about any three orthopedic problems.
Answer:

Common orthopedic problems:

Anything that is concerned with muscles, ligaments, and joints is considered orthopedic. Some common problems are

1. Arthritis is a rheumatic disease that has symptoms of pain, limited movement, swelling, and pain in connective tissues.
2. Osteoarthritis is a degenerative joint disease that middle-aged and older adults experience. The joint cartilage breaks down with the progress of your age and it can occur in the hands, knees, spine, or hips.
3. Rheumatoid arthritis is a disease listed in the orthopedic section that causes severe inflammation of the joints. joints. The inflammation is so severe that the functioning of the extremities becomes severely limited.
4. Fractures are definite orthopedic problems.
5. Low back pain is an orthopedic condition that affects one in ten people. Low back pain presents from mild and annoying to persistent and severe.
6. Neck pain can come from injuries or damage to the muscles and ligaments of the neck, a herniated cervical disk of arthritis.

2. Bone Joints

The human body moves in many different ways. You can bend, stretch, turn, and twist. You can move because your bones move at your joints, places where your bones meet.

But your bones can’t move by themselves-they need muscles, which are joined to your bones in order to move them.

There are many joints that help your body move. When you turn your head, bend your knees, or twist your wrists, your joints are in action. Some joints, such as those in your skull, do not move.

These are called fixed joints. Each of the other kinds of joints does a specific type of movement.

What are joints? Joints are places where bones meet. The study of joints is called “arthrology”, which is derived from the Greek words “Atheros” meaning joint, and “logos” meaning study.

One bone can have two or more joints. An example is your jaw or mandible. It is connected to the temporal bones on either side of your skull.

You can feel these joints when you place your hands on the junction of your cheeks and your ears and simulate chewing motions.

Question 7. Classify joints according to the material of their union.
Answer:

Bones, Bone-Joints, and Muscles

Every time you move your body from place to place, your bones, muscles, and joints are working together. The bones that make up your skeletal system provide shape and protection.

Your skull protects your brain, your backbones protect your spinal cord and your ribs protect your heart and lungs.

Wherever two bones meet, there is a joint to hold them together and allow them to move, but there would be no movement without the 650 muscles that make up your muscular system.

Bones form the structural framework for our body, while muscles are responsible for pulling the joints, allowing us to move.

The cartilage, muscles, ligaments, and tendons, all work as one, holding bones together and letting joints move. Muscles connect the joints to the bones.

Flexing of the muscles and the ability to bend at the joints moves the bones to accomplish skilled body motions.

1. Bones

Bones make up the framework of our bodies. We call this framework the skeleton. Bones are living, growing, and changing parts of our bodies.

Baby skeletons are made up of more than 300 parts, but by the time we become adults we only have 206 bones. No, we don’t lose any.

It’s just that some of our baby bones are made, partly or completely, of cartilage. As we grow bigger and heavier, cartilage is slowly replaced by harder bone.

Some smaller bones are joined together to make one bigger bone.

Bones are largely made of calcium and other minerals. They are hard enough to support our weight and daily stress. Bones protect our major organs and give our bodies shape.

Bones are actually living tissue. The center of the bone, or marrow, is where your blood is created.

Parts of bones:  Most bones have 4 parts:

1. The outside part of the bone is called the periosteum. This is a thin but very dense layer that has the nerves and blood vessels which nourish the bone.
2.  Compact bone is next. It is smooth and very hard.
3. Cancellous bone comes next and this looks a bit like a sponge but is much stronger.
4. On the very inside of many bones is the bone marrow. It looks a bit like a jelly and it makes new blood cells for the body.

Functions of bones:

1. The bones of the skeleton give us our shape and our posture. Without our spine (backbone) and leg bones, we would be unable to stand erect. Bones also protect the softer parts of our bodies.
2. The skull is like a natural helmet that protects the brain.
3. The spine protects the nerves in the spinal column.
4. The rib makes a shield around our lungs and heart.
5. They act as a base for muscles, ligaments, and tendons. Ligaments connect bones to bones and tendons connect muscles to bones.
6. They all work together to help us move around.

 

 

Different major bony parts of our body

1. Some bones protect the brain. You can feel the bone at the back of your head and forehead.
2. Some bones make the framework for your face. You can feel the bones around your eyes.
3. Some bones in the middle part of your ear carry sound from your eardrum to the inner De ear.
4. You can feel the jawbone under your chin and where it hinges just under your ear. It is the only bone in your skull that you can move.

2. Spine (Vertebral Column)

The spine has 26 bones which are like circles with wings on the sides and back. They are called vertebrae. There are small discs made of cartilage between each vertebra.

They act like shock absorbers and stop the bones from rubbing against each other. There is also a hole through each of the vertebrae where the spinal cord goes.

1. The top 7 are called the cervical vertebrae and they support your head and neck.
2. The next 12 are called the thoracic vertebrae. These hold one end of your ribs.
3. The next 5 are the lumber vertebrae.
4. The next, the sacrum, is a large bone that is actually made of 5 vertebrae fused (joined) together.
5. At the bottom of the spine is the coccyx, which is one bone made of 4 small vertebrae fused together.

 

 

3. Ribs

Ribs make a protective cage around your lungs and heart. There are usually 12 pairs of ribs, each pair attached to the spine at the back.

Each rib is attached to the ribs above and below it by muscles and ligaments.

1. At the front of the body, the top 7 ribs are attached to the sternum (or breast bone).
2. The next 3 pairs are joined to the ribs above and to the sternum, by cartilage.
3. The last 2 pairs of ribs are called the ‘floating’ ribs. They are called floating because they are attached only to the vertebrae and not to the sternum. They don’t have sharp edges sticking out.

4. Arms

Each arm is fastened to the scapula (the shoulder blade) at the back, (which is a triangle-shaped bone near the top of the ribs) and to the clavicle at the front (the collar bone).

The arm has 3 bones-the humerus, the radius, and the ulna. The humerus is the bone between your shoulder and the elbow.

The radius and ulna bones go from the elbow to the wrist. At the end of the radius and ulna is your wrist. Your wrist has 8 small bones, so it is really flexible. In each hand, there are 19 bones.

5. Legs

Your legs are fastened to your pelvis at the hips. The pelvis is shaped like a bowl and supports the contents of your tummy.

1. Legs need to be large and strong to support something to pull them. This job is done by the rest of the body.
2. The femur is the largest bone in the body and it goes from the pelvis to the knee.
3. Another bone called the patella, or kneecap covers the knee joint to protect it.
4. Below the knee, there are 2 bones. These are the tibia and the fibula. They join up to a large bone in the ankle called the talus.
5. There are 6 other bones here so you can move your ankle around but you cannot move it as much as you can move your wrist. Your feet and ankles have a total of 52 bones in them.

 

 

Common orthopedic problems:

Anything that is concerned with muscles, ligaments, and joints is considered orthopedic. Some common problems are

1. Arthritis is a rheumatic disease that has symptoms of pain, limited movement, swelling, and pain in connective tissues.
2. Osteoarthritis is a degenerative joint disease that middle-aged and older adults experience. The joint cartilage breaks down with the progress of your age and it can occur in the hands, knees, spine, or hips.
3. Rheumatoid arthritis is a disease listed in the orthopedic section that causes severe inflammation of the joints. joints. The inflammation is so severe that the functioning of the extremities becomes severely limited.
4. Fractures are definite orthopedic problems.
5. Low back pain is an orthopedic condition that affects one in ten people. Low back pain presents from mild and annoying to persistent and severe.
6. Neck pain can come from injuries or damage to the muscles and ligaments of the neck, a herniated cervical disk of arthritis.

2. Bone Joints

The human body moves in many different ways. You can bend, stretch, turn, and twist. You can move because your bones move at your joints, places where your bones meet.

But your bones can’t move by themselves-they need muscles, which are joined to your bones in order to move them.

There are many joints that help your body move. When you turn your head, bend your knees, or twist your wrists, your joints are in action. Some joints, such as those in your skull, do not move.

These are called fixed joints. Each of the other kinds of joints does a specific type of movement.

What are joints? Joints are places where bones meet. The study of joints is called “arthrology”, which is derived from the Greek words “Atheros” meaning joint, and “logos” meaning study.

One bone can have two or more joints. An example is your jaw or mandible. It is connected to the temporal bones on either side of your skull.

You can feel these joints when you place your hands on the junction of your cheeks and your ears and simulate chewing motions.

What are the functions of your joints:

Aside from smooth movement, joints also have other functions. They allow you to grow. When your brain grows, the sutures in your skull accommodate.

The primary cartilaginous joints of your knees and elbows allow you to grow to your full height. Joints also serve to minimize friction and cushion the bones against impact.

Joints are very important areas in your body. They give you space for growth and allow you to move the way you want.

What are the classifications of joints:

Joints can be classified according to what material unites the bones. The three main types of joints are fibrous joints, cartilaginous joints, and synovial joints.

Fibrous joints are joined by fibrous tissue cartilaginous joints are united by cartilage or a mix of cartilage and fibrous tissue; synovial joints are connected by a synovial membrane that surrounds the joint cavity.

1. Fibrous joints:

The movement allowed by these joints is dependent on the length of the fibrous tissue connecting the bones. In the skull, these joints are called sutures.

Sutures are connected by strong connective tissues and allow very little or no movement in adults. These are known as immovable joints.

 

 

2. Cartilaginous joints:

These joints can be primary cartilaginous joints and secondary cartilaginous joints. Primary cartilaginous joints are connected by cartilage temporarily, early in life.

An example is your knee joint. Later on, the cartilage becomes bone. Secondary cartilaginous joints. consist of bones with the ends covered by cartilage and connected with fibrous. tissue.

These joints are found in the vertebral column and allow slight movement. These are known as partly movable joints.

3. Synovial joints:

These joints are present in the shoulder, hip, knee, ankle, toes, elbow, and the joints of the limbs including the loot fingers.

Their name is derived from the fact sling that they have synovial fluid and is du enclosed within a synovial capsule.

joints allow considerable movement but have ligaments to prevent excessive movement. These are known as movable lee joints.

What are the types of synovial joints?

Synovial joints can be categorized into six types based on the movement they allow. The first type, a plane joint, allows gliding or sliding movement, and the bones involved usually have flat surfaces.

An example of a plane joint is found in the shoulder, between the shoulder blade (acromion of the scapula) and the clavicle.

A hinge joint can move in the axis at a right angle to the joints involved. An example is the elbow joint, which connects the humerus and the ulna.

The movement allowed by this joint includes flexion (bending) and extension (straightening) of your elbow.
The third type of synovial joint is the condyloid joint.

In Greek, “condyloid” means knuckle-like. This type of joint allows movement in two axes. Therefore you can bend it, straighten it, move it from side to side, and rotate it.

An example is your wrist joint. song yen send scrawled The fourth synovial joint type is the saddle joint.

 

 

This joint is so-named because the opposing surfaces of the involved bones look like a saddle-one has a convex surface, while the other has a concave surface.

The thumb joint, which can also move in two axes, is a good example of this joint.

Ball and socket joints are perhaps the most versatile synovial joints. They are multi-axial joints, which means they can move in many axes. One joint has a ball and the other joint has a socket.

The shoulder joint and the hip joints are examples of this type. In the hip joint, the ball is the head of the leg bone (femur) while the socket is the acetabulum of the hip (pelvis).

Try to experiment with the kinds of movement you can make with your hip joint. You can bend, flex, open, close, rotate and circularly move your legs.

These movements of the hip joint are very important for ballerinas and dancers who have complex leg routines.

The last type of synovial joint is the pivot joint. These joints only allow rotation. One bone serves like a ring while the other bone has a rounded process rotating within the ring.

This type is found in your neck, particularly in your first two cervical bones called the atlas (the ring) and the dens (the rounded process). This allows you to rotate your head.

Problems of bone joints:

Joints form the connections between bones. They provide support and help you move. Any damage to the joints from disease or injury can interfere with your movement and cause a lot of pain.

Joint pain can be caused by injury affecting any of the ligaments, bursae, or tendons surrounding the joint. Injury can also affect the ligaments, cartilage, and bones within the joint.

Many different conditions can lead to painful joints including osteoarthritis, rheumatoid arthritis, bursitis, gout, strains, sprains, and other injuries. Joint pain is extremely common.

Joint pain can range from mildly irritating to debilitating. It may go away after a few weeks (acute), or last for several weeks or months (chronic).

Even short-term pain and swelling in the joints can affect your quality of life. Whatever the cause of joint pain, you can usually manage it with medication, physical therapy, or alternative treatments.

3. Muscles

Did you know you have more than 600 muscles in your body? They do everything from pumping blood throughout your body to helping you lift your heavy backpack.

You control some of your muscles, while others–like your heart- do their jobs without you thinking about them at all.

Muscles are all made of the same material, a type of elastic tissue (sort of like the material in a rubber band). Thousands or even tens of thousands of small fibers make up each muscle.

Types of muscles:

You have three different types of muscles in your body: smooth muscle, cardiac muscle, and skeletal muscle.

1. Smooth muscles or Involuntary muscles

Smooth muscles-sometimes also called involuntary muscles-are usually in sheets, or layers, with one layer of muscle behind the other. You cannot control this type of muscle.

Your brain and body tell these muscles what to do without you even thinking about it. But smooth muscles are at work all over your body.

In your stomach and digestive system, they contract (tighten up) and relax to allow food to make its journey through the body. Smooth muscles are also found in your bladder.

When they are relaxed, they allow you to hold in urine until you can get to the bathroom. Then they contract so that you can push the urine out.

2. Cardiac muscles

The muscle that makes up the heart is called cardiac muscle. It is also known as the myocardium. The thick muscles of the heart contract to pump blood out and then relax to let blood in after it has circulated through the body.

Just like smooth muscle, cardiac muscle works all by itself with no help from you. A special group of cells within the heart are known as the pacemaker of the heart because it controls the heartbeat.

3. Straited muscles or Voluntary muscles

Now, let’s talk about the kind of muscle you think of when we say “muscle”-the ones that show how strong you are and let you boot a soccer ball into the goal.

These are your skeletal muscles-sometimes called striated muscles because the light and dark parts of the muscle fibers make them look striped. are voluntary muscles, which means you can control what they do.

Your leg will not bend to kick the soccer ball unless you want it to. These muscles help to make up the musculoskeletal system-the combination of your muscles and your skeleton, or bones.

Skeletal muscles are held to the bones with the help of tendons Tendons are cords made of tough tissue, and they work as special connector pieces between bone and muscle.

The tendons are attached so well that when you contract one of your muscles, the tendon and bone move along with it.

Skeletal muscles also give your body the power it needs to lift and push things. Muscles in your neck and the top part of your back aren’t as large, but they are capable of some pretty amazing things.

Try rotating your head around, back and forth, and up and down to feel the power of the muscles in your neck. These muscles also hold your head high.

How do muscles work? Muscles work by expanding and contracting. Muscles have long, thin cells that are grouped into bundles.

When a muscle fiber gets a signal from its nerve, proteins, and chemicals release energy to either contract the muscle or relax it.

When the muscle contracts, this pulls the bones it’s connected to, closer together. Many of our muscles come in pairs. An example of this is the biceps and triceps in our arms.

When the biceps contract the triceps will relax, which allows our arm to bend. When we want to straighten our arm back out, the biceps will relax and the triceps will contract.

Muscle pairs allow us to move back and forth. Caring muscles Muscles get most of their energy from glucose.

Glucose is made from several types of carbohydrates such as sucrose (which is usually called sugar), lactose (from milk), or fructose (from fruits).

When muscles need to get energy from glucose they do this by changing the glucose into other chemicals such as water and carbon dioxide which release the energy.

We sometimes call this ‘burning’ glucose. They use the oxygen being carried in the blood to help them do this.

Muscles need to move to remain healthy and strong. You can help your muscles stay strong and healthy by exercising every day and using moms have different sets of muscles when they exercise.

When you exercise a lot, your muscles become tired from all the contracting and relaxing. Your muscles might get hurt then.

Have you ever had a cramp? This is when your muscles seem to lock up, and you have a pain in your foot or your leg, or a ‘stitch’ in your side.

This happens when one or more of your muscles contract and will not relax again (called a spasm).

Sweating and not drinking enough on a hot day may mean that you are more likely to get a muscle cramp.
Try drinking water, and stretching and massaging the muscle that hurts and it will get better.

Diseases that can affect muscles: Polio is a virus that attacks the spinal cord. The brain can’t send messages to the muscles and they stop working.

Not long ago a lot of kids would catch this illness, but nowadays not many people get poliomyelitis (that’s its full name) because kids are given an immunization against it.

Tetanus also affects muscles and kids have already had ‘shots’ to stop them from getting this too. There are some other diseases that can affect muscles.

If a person spends long hours in front of a computer then he may sustain injuries from occupational poor posture. The most common such injuries are

1. Mouse shoulder.
2. Computer back
3. Lumbar strains and sprains
4. Disc injuries
5. Tennis elbow.

 

Question 8. Describe the synovial joint.
Answer:

Bones, Bone-Joints, and Muscles

Every time you move your body from place to place, your bones, muscles, and joints are working together. The bones that make up your skeletal system provide shape and protection.

Your skull protects your brain, your backbones protect your spinal cord and your ribs protect your heart and lungs.

Wherever two bones meet, there is a joint to hold them together and allow them to move, but there would be no movement without the 650 muscles that make up your muscular system.

Bones form the structural framework for our body, while muscles are responsible for pulling the joints, allowing us to move.

The cartilage, muscles, ligaments, and tendons, all work as one, holding bones together and letting joints move. Muscles connect the joints to the bones.

Flexing of the muscles and the ability to bend at the joints moves the bones to accomplish skilled body motions.

1. Bones

Bones make up the framework of our bodies. We call this framework the skeleton. Bones are living, growing, and changing parts of our bodies.

Baby skeletons are made up of more than 300 parts, but by the time we become adults we only have 206 bones. No, we don’t lose any.

It’s just that some of our baby bones are made, partly or completely, of cartilage. As we grow bigger and heavier, cartilage is slowly replaced by harder bone.

Some smaller bones are joined together to make one bigger bone.

Bones are largely made of calcium and other minerals. They are hard enough to support our weight and daily stress. Bones protect our major organs and give our bodies shape.

Bones are actually living tissue. The center of the bone, or marrow, is where your blood is created.

Parts of bones:  Most bones have 4 parts:

1. The outside part of the bone is called the periosteum. This is a thin but very dense layer that has the nerves and blood vessels which nourish the bone.
2.  Compact bone is next. It is smooth and very hard.
3. Cancellous bone comes next and this looks a bit like a sponge but is much stronger.
4. On the very inside of many bones is the bone marrow. It looks a bit like a jelly and it makes new blood cells for the body.

Functions of bones:

1. The bones of the skeleton give us our shape and our posture. Without our spine (backbone) and leg bones, we would be unable to stand erect. Bones also protect the softer parts of our bodies.
2. The skull is like a natural helmet that protects the brain.
3. The spine protects the nerves in the spinal column.
4. The rib makes a shield around our lungs and heart.
5. They act as a base for muscles, ligaments, and tendons. Ligaments connect bones to bones and tendons connect muscles to bones.
6. They all work together to help us move around.

 

 

Different major bony parts of our body

1. Some bones protect the brain. You can feel the bone at the back of your head and forehead.
2. Some bones make the framework for your face. You can feel the bones around your eyes.
3. Some bones in the middle part of your ear carry sound from your eardrum to the inner De ear.
4. You can feel the jawbone under your chin and where it hinges just under your ear. It is the only bone in your skull that you can move.

2. Spine (Vertebral Column)

The spine has 26 bones which are like circles with wings on the sides and back. They are called vertebrae. There are small discs made of cartilage between each vertebra.

They act like shock absorbers and stop the bones from rubbing against each other. There is also a hole through each of the vertebrae where the spinal cord goes.

1. The top 7 are called the cervical vertebrae and they support your head and neck.
2. The next 12 are called the thoracic vertebrae. These hold one end of your ribs.
3. The next 5 are the lumber vertebrae.
4. The next, the sacrum, is a large bone that is actually made of 5 vertebrae fused (joined) together.
5. At the bottom of the spine is the coccyx, which is one bone made of 4 small vertebrae fused together.

 

 

3. Ribs

Ribs make a protective cage around your lungs and heart. There are usually 12 pairs of ribs, each pair attached to the spine at the back.

Each rib is attached to the ribs above and below it by muscles and ligaments.

1. At the front of the body, the top 7 ribs are attached to the sternum (or breast bone).
2. The next 3 pairs are joined to the ribs above and to the sternum, by cartilage.
3. The last 2 pairs of ribs are called the ‘floating’ ribs. They are called floating because they are attached only to the vertebrae and not to the sternum. They don’t have sharp edges sticking out.

4. Arms

Each arm is fastened to the scapula (the shoulder blade) at the back, (which is a triangle-shaped bone near the top of the ribs) and to the clavicle at the front (the collar bone).

The arm has 3 bones-the humerus, the radius, and the ulna. The humerus is the bone between your shoulder and the elbow.

The radius and ulna bones go from the elbow to the wrist. At the end of the radius and ulna is your wrist. Your wrist has 8 small bones, so it is really flexible. In each hand, there are 19 bones.

5. Legs

Your legs are fastened to your pelvis at the hips. The pelvis is shaped like a bowl and supports the contents of your tummy.

1. Legs need to be large and strong to support something to pull them. This job is done by the rest of the body.
2. The femur is the largest bone in the body and it goes from the pelvis to the knee.
3. Another bone called the patella, or kneecap covers the knee joint to protect it.
4. Below the knee, there are 2 bones. These are the tibia and the fibula. They join up to a large bone in the ankle called the talus.
5. There are 6 other bones here so you can move your ankle around but you cannot move it as much as you can move your wrist. Your feet and ankles have a total of 52 bones in them.

 

 

Common orthopedic problems:

Anything that is concerned with muscles, ligaments, and joints is considered orthopedic. Some common problems are

1. Arthritis is a rheumatic disease that has symptoms of pain, limited movement, swelling, and pain in connective tissues.
2. Osteoarthritis is a degenerative joint disease that middle-aged and older adults experience. The joint cartilage breaks down with the progress of your age and it can occur in the hands, knees, spine, or hips.
3. Rheumatoid arthritis is a disease listed in the orthopedic section that causes severe inflammation of the joints. joints. The inflammation is so severe that the functioning of the extremities becomes severely limited.
4. Fractures are definite orthopedic problems.
5. Low back pain is an orthopedic condition that affects one in ten people. Low back pain presents from mild and annoying to persistent and severe.
6. Neck pain can come from injuries or damage to the muscles and ligaments of the neck, a herniated cervical disk of arthritis.

2. Bone Joints

The human body moves in many different ways. You can bend, stretch, turn, and twist. You can move because your bones move at your joints, places where your bones meet.

But your bones can’t move by themselves-they need muscles, which are joined to your bones in order to move them.

There are many joints that help your body move. When you turn your head, bend your knees, or twist your wrists, your joints are in action. Some joints, such as those in your skull, do not move.

These are called fixed joints. Each of the other kinds of joints does a specific type of movement.

What are joints? Joints are places where bones meet. The study of joints is called “arthrology”, which is derived from the Greek words “Atheros” meaning joint, and “logos” meaning study.

One bone can have two or more joints. An example is your jaw or mandible. It is connected to the temporal bones on either side of your skull.

You can feel these joints when you place your hands on the junction of your cheeks and your ears and simulate chewing motions.

What are the functions of your joints:

Aside from smooth movement, joints also have other functions. They allow you to grow. When your brain grows, the sutures in your skull accommodate.

The primary cartilaginous joints of your knees and elbows allow you to grow to your full height. Joints also serve to minimize friction and cushion the bones against impact.

Joints are very important areas in your body. They give you space for growth and allow you to move the way you want.

What are the classifications of joints:

Joints can be classified according to what material unites the bones. The three main types of joints are fibrous joints, cartilaginous joints, and synovial joints.

Fibrous joints are joined by fibrous tissue cartilaginous joints are united by cartilage or a mix of cartilage and fibrous tissue; synovial joints are connected by a synovial membrane that surrounds the joint cavity.

1. Fibrous joints:

The movement allowed by these joints is dependent on the length of the fibrous tissue connecting the bones. In the skull, these joints are called sutures.

Sutures are connected by strong connective tissues and allow very little or no movement in adults. These are known as immovable joints.

 

 

2. Cartilaginous joints:

These joints can be primary cartilaginous joints and secondary cartilaginous joints. Primary cartilaginous joints are connected by cartilage temporarily, early in life.

An example is your knee joint. Later on, the cartilage becomes bone. Secondary cartilaginous joints. consist of bones with the ends covered by cartilage and connected with fibrous. tissue.

These joints are found in the vertebral column and allow slight movement. These are known as partly movable joints.

3. Synovial joints:

These joints are present in the shoulder, hip, knee, ankle, toes, elbow, and the joints of the limbs including the loot fingers.

Their name is derived from the fact sling that they have synovial fluid and is du enclosed within a synovial capsule.

Joints allow considerable movement but have ligaments to prevent excessive movement. These are known as movable lee joints.

What are the types of synovial joints?

Synovial joints can be categorized into six types based on the movement they allow. The first type, a plane joint, allows gliding or sliding movement, and the bones involved usually have flat surfaces.

An example of a plane joint is found in the shoulder, between the shoulder blade (acromion of the scapula) and the clavicle.

A hinge joint can move in the axis at a right angle to the joints involved. An example is the elbow joint, which connects the humerus and the ulna.

The movement allowed by this joint includes flexion (bending) and extension (straightening) of your elbow.
The third type of synovial joint is the condyloid joint.

In Greek, “condyloid” means knuckle-like. This type of joint allows movement in two axes. Therefore you can bend it, straighten it, move it from side to side, and rotate it.

An example is your wrist joint. song yen send scrawled The fourth synovial joint type is the saddle joint.

 

 

This joint is so-named because the opposing surfaces of the involved bones look like a saddle-one has a convex surface, while the other has a concave surface.

The thumb joint, which can also move in two axes, is a good example of this joint.

Ball and socket joints are perhaps the most versatile synovial joints. They are multi-axial joints, which means they can move in many axes. One joint has a ball and the other joint has a socket.

The shoulder joint and the hip joints are examples of this type. In the hip joint, the ball is the head of the leg bone (femur) while the socket is the acetabulum of the hip (pelvis).

Try to experiment with the kinds of movement you can make with your hip joint. You can bend, flex, open, close, rotate and circularly move your legs.

These movements of the hip joint are very important for ballerinas and dancers who have complex leg routines.

The last type of synovial joint is the pivot joint. These joints only allow rotation. One bone serves like a ring while the other bone has a rounded process rotating within the ring.

This type is found in your neck, particularly in your first two cervical bones called the atlas (the ring) and the dens (the rounded process). This allows you to rotate your head.

Problems of bone joints:

Joints form the connections between bones. They provide support and help you move. Any damage to the joints from disease or injury can interfere with your movement and cause a lot of pain.

Joint pain can be caused by injury affecting any of the ligaments, bursae, or tendons surrounding the joint. Injury can also affect the ligaments, cartilage, and bones within the joint.

Many different conditions can lead to painful joints including osteoarthritis, rheumatoid arthritis, bursitis, gout, strains, sprains, and other injuries. Joint pain is extremely common.

Joint pain can range from mildly irritating to debilitating. It may go away after a few weeks (acute), or last for several weeks or months (chronic).

Even short-term pain and swelling in the joints can affect your quality of life. Whatever the cause of joint pain, you can usually manage it with medication, physical therapy, or alternative treatments.

3. Muscles

Did you know you have more than 600 muscles in your body? They do everything from pumping blood throughout your body to helping you lift your heavy backpack.

You control some of your muscles, while others–like your heart- do their jobs without you thinking about them at all.

Muscles are all made of the same material, a type of elastic tissue (sort of like the material in a rubber band). Thousands or even tens of thousands of small fibers make up each muscle.

Types of muscles:

You have three different types of muscles in your body: smooth muscle, cardiac muscle, and skeletal muscle.

1. Smooth muscles or Involuntary muscles

Smooth muscles-sometimes also called involuntary muscles-are usually in sheets, or layers, with one layer of muscle behind the other. You cannot control this type of muscle.

Your brain and body tell these muscles what to do without you even thinking about it. But smooth muscles are at work all over your body.

In your stomach and digestive system, they contract (tighten up) and relax to allow food to make its journey through the body. Smooth muscles are also found in your bladder.

When they are relaxed, they allow you to hold in urine until you can get to the bathroom. Then they contract so that you can push the urine out.

2. Cardiac muscles

The muscle that makes up the heart is called cardiac muscle. It is also known as the myocardium. The thick muscles of the heart contract to pump blood out and then relax to let blood in after it has circulated through the body.

Just like smooth muscle, cardiac muscle works all by itself with no help from you. A special group of cells within the heart are known as the pacemaker of the heart because it controls the heartbeat.

3. Straited muscles or Voluntary muscles

Now, let’s talk about the kind of muscle you think of when we say “muscle”-the ones that show how strong you are and let you boot a soccer ball into the goal.

These are your skeletal muscles-sometimes called striated muscles because the light and dark parts of the muscle fibers make them look striped. are voluntary muscles, which means you can control what they do.

Your leg will not bend to kick the soccer ball unless you want it to. These muscles help to make up the musculoskeletal system-the combination of your muscles and your skeleton, or bones.

Skeletal muscles are held to the bones with the help of tendons Tendons are cords made of tough tissue, and they work as special connector pieces between bone and muscle.

The tendons are attached so well that when you contract one of your muscles, the tendon and bone move along with it.

Skeletal muscles also give your body the power it needs to lift and push things. Muscles in your neck and the top part of your back aren’t as large, but they are capable of some pretty amazing things.

Try rotating your head around, back and forth, and up and down to feel the power of the muscles in your neck. These muscles also hold your head high.

How do muscles work? Muscles work by expanding and contracting. Muscles have long, thin cells that are grouped into bundles.

When a muscle fiber gets a signal from its nerve, proteins, and chemicals release energy to either contract the muscle or relax it.

When the muscle contracts, this pulls the bones it’s connected to, closer together. Many of our muscles come in pairs. An example of this is the biceps and triceps in our arms.

When the biceps contract the triceps will relax, which allows our arm to bend. When we want to straighten our arm back out, the biceps will relax and the triceps will contract.

Muscle pairs allow us to move back and forth. Caring muscles Muscles get most of their energy from glucose.

Glucose is made from several types of carbohydrates such as sucrose (which is usually called sugar), lactose (from milk), or fructose (from fruits).

When muscles need to get energy from glucose they do this by changing the glucose into other chemicals such as water and carbon dioxide which release the energy.

We sometimes call this ‘burning’ glucose. They use the oxygen being carried in the blood to help them do this.

Muscles need to move to remain healthy and strong. You can help your muscles stay strong and healthy by exercising every day and using moms have different sets of muscles when they exercise.

When you exercise a lot, your muscles become tired from all the contracting and relaxing. Your muscles might get hurt then.

Have you ever had a cramp? This is when your muscles seem to lock up, and you have a pain in your foot or your leg, or a ‘stitch’ in your side.

This happens when one or more of your muscles contract and will not relax again (called a spasm).

Sweating and not drinking enough on a hot day may mean that you are more likely to get a muscle cramp.
Try drinking water, and stretching and massaging the muscle that hurts and it will get better.

Diseases that can affect muscles: Polio is a virus that attacks the spinal cord. The brain can’t send messages to the muscles and they stop working.

Not long ago a lot of kids would catch this illness, but nowadays not many people get poliomyelitis (that’s its full name) because kids are given an immunization against it.

Tetanus also affects muscles and kids have already had ‘shots’ to stop them from getting this too. There are some other diseases that can affect muscles.

If a person spends long hours in front of a computer then he may sustain injuries from occupational poor posture. The most common such injuries are

1. Mouse shoulder.
2. Computer back
3. Lumbar strains and sprains
4. Disc injuries
5. Tennis elbow.

 

Question 9. Write about different types of muscles found in our body.
Answer:

Bones, Bone-Joints, and Muscles

Every time you move your body from place to place, your bones, muscles, and joints are working together. The bones that make up your skeletal system provide shape and protection.

Your skull protects your brain, your backbones protect your spinal cord and your ribs protect your heart and lungs.

Wherever two bones meet, there is a joint to hold them together and allow them to move, but there would be no movement without the 650 muscles that make up your muscular system.

Bones form the structural framework for our body, while muscles are responsible for pulling the joints, allowing us to move.

The cartilage, muscles, ligaments, and tendons, all work as one, holding bones together and letting joints move. Muscles connect the joints to the bones.

Flexing of the muscles and the ability to bend at the joints moves the bones to accomplish skilled body motions.

1. Bones

Bones make up the framework of our bodies. We call this framework the skeleton. Bones are living, growing, and changing parts of our bodies.

Baby skeletons are made up of more than 300 parts, but by the time we become adults we only have 206 bones. No, we don’t lose any.

It’s just that some of our baby bones are made, partly or completely, of cartilage. As we grow bigger and heavier, cartilage is slowly replaced by harder bone.

Some smaller bones are joined together to make one bigger bone.

Bones are largely made of calcium and other minerals. They are hard enough to support our weight and daily stress. Bones protect our major organs and give our bodies shape.

Bones are actually living tissue. The center of the bone, or marrow, is where your blood is created.

Parts of bones:  Most bones have 4 parts:

1. The outside part of the bone is called the periosteum. This is a thin but very dense layer that has the nerves and blood vessels which nourish the bone.
2.  Compact bone is next. It is smooth and very hard.
3. Cancellous bone comes next and this looks a bit like a sponge but is much stronger.
4. On the very inside of many bones is the bone marrow. It looks a bit like a jelly and it makes new blood cells for the body.

Functions of bones:

1. The bones of the skeleton give us our shape and our posture. Without our spine (backbone) and leg bones, we would be unable to stand erect. Bones also protect the softer parts of our bodies.
2. The skull is like a natural helmet that protects the brain.
3. The spine protects the nerves in the spinal column.
4. The rib makes a shield around our lungs and heart.
5. They act as a base for muscles, ligaments, and tendons. Ligaments connect bones to bones and tendons connect muscles to bones.
6. They all work together to help us move around.

 

 

Different major bony parts of our body

1. Some bones protect the brain. You can feel the bone at the back of your head and forehead.
2. Some bones make the framework for your face. You can feel the bones around your eyes.
3. Some bones in the middle part of your ear carry sound from your eardrum to the inner De ear.
4. You can feel the jawbone under your chin and where it hinges just under your ear. It is the only bone in your skull that you can move.

2. Spine (Vertebral Column)

The spine has 26 bones which are like circles with wings on the sides and back. They are called vertebrae. There are small discs made of cartilage between each vertebra.

They act like shock absorbers and stop the bones from rubbing against each other. There is also a hole through each of the vertebrae where the spinal cord goes.

 

1. The top 7 are called the cervical vertebrae and they support your head and neck.
2. The next 12 are called the thoracic vertebrae. These hold one end of your ribs.
3. The next 5 are the lumber vertebrae.
4. The next, the sacrum, is a large bone that is actually made of 5 vertebrae fused (joined) together.
5. At the bottom of the spine is the coccyx, which is one bone made of 4 small vertebrae fused together.

 

 

3. Ribs

Ribs make a protective cage around your lungs and heart. There are usually 12 pairs of ribs, each pair attached to the spine at the back.

Each rib is attached to the ribs above and below it by muscles and ligaments.

1. At the front of the body, the top 7 ribs are attached to the sternum (or breast bone).
2. The next 3 pairs are joined to the ribs above and to the sternum, by cartilage.
3. The last 2 pairs of ribs are called the ‘floating’ ribs. They are called floating because they are attached only to the vertebrae and not to the sternum. They don’t have sharp edges sticking out.

4. Arms

Each arm is fastened to the scapula (the shoulder blade) at the back, (which is a triangle-shaped bone near the top of the ribs) and to the clavicle at the front (the collar bone).

The arm has 3 bones-the humerus, the radius, and the ulna. The humerus is the bone between your shoulder and the elbow.

The radius and ulna bones go from the elbow to the wrist. At the end of the radius and ulna is your wrist. Your wrist has 8 small bones, so it is really flexible. In each hand, there are 19 bones.

5. Legs

Your legs are fastened to your pelvis at the hips. The pelvis is shaped like a bowl and supports the contents of your tummy.

1. Legs need to be large and strong to support something to pull them. This job is done by the rest of the body.
2. The femur is the largest bone in the body and it goes from the pelvis to the knee.
3. Another bone called the patella, or kneecap covers the knee joint to protect it.
4. Below the knee, there are 2 bones. These are the tibia and the fibula. They join up to a large bone in the ankle called the talus.
5. There are 6 other bones here so you can move your ankle around but you cannot move it as much as you can move your wrist. Your feet and ankles have a total of 52 bones in them.

 

 

Common orthopedic problems:

Anything that is concerned with muscles, ligaments, and joints is considered orthopedic. Some common problems are

1. Arthritis is a rheumatic disease that has symptoms of pain, limited movement, swelling, and pain in connective tissues.
2. Osteoarthritis is a degenerative joint disease that middle-aged and older adults experience. The joint cartilage breaks down with the progress of your age and it can occur in the hands, knees, spine, or hips.
3. Rheumatoid arthritis is a disease listed in the orthopedic section that causes severe inflammation of the joints. joints. The inflammation is so severe that the functioning of the extremities becomes severely limited.
4. Fractures are definite orthopedic problems.
5. Low back pain is an orthopedic condition that affects one in ten people. Low back pain presents from mild and annoying to persistent and severe.
6. Neck pain can come from injuries or damage to the muscles and ligaments of the neck, a herniated cervical disk of arthritis.

2. Bone Joints

The human body moves in many different ways. You can bend, stretch, turn, and twist. You can move because your bones move at your joints, places where your bones meet.

But your bones can’t move by themselves-they need muscles, which are joined to your bones in order to move them.

There are many joints that help your body move. When you turn your head, bend your knees, or twist your wrists, your joints are in action. Some joints, such as those in your skull, do not move.

These are called fixed joints. Each of the other kinds of joints does a specific type of movement.

What are joints? Joints are places where bones meet. The study of joints is called “arthrology”, which is derived from the Greek words “Atheros” meaning joint, and “logos” meaning study.

One bone can have two or more joints. An example is your jaw or mandible. It is connected to the temporal bones on either side of your skull.

You can feel these joints when you place your hands on the junction of your cheeks and your ears and simulate chewing motions.

What are the functions of your joints:

Aside from smooth movement, joints also have other functions. They allow you to grow. When your brain grows, the sutures in your skull accommodate.

The primary cartilaginous joints of your knees and elbows allow you to grow to your full height. Joints also serve to minimize friction and cushion the bones against impact.

Joints are very important areas in your body. They give you space for growth and allow you to move the way you want.

What are the classifications of joints:

Joints can be classified according to what material unites the bones. The three main types of joints are fibrous joints, cartilaginous joints, and synovial joints.

Fibrous joints are joined by fibrous tissue cartilaginous joints are united by cartilage or a mix of cartilage and fibrous tissue; synovial joints are connected by a synovial membrane that surrounds the joint cavity.

1. Fibrous joints:

The movement allowed by these joints is dependent on the length of the fibrous tissue connecting the bones. In the skull, these joints are called sutures.

Sutures are connected by strong connective tissues and allow very little or no movement in adults. These are known as immovable joints.

 

 

2. Cartilaginous joints:

These joints can be primary cartilaginous joints and secondary cartilaginous joints. Primary cartilaginous joints are connected by cartilage temporarily, early in life.

An example is your knee joint. Later on, the cartilage becomes bone. Secondary cartilaginous joints. consist of bones with the ends covered by cartilage and connected with fibrous. tissue.

These joints are found in the vertebral column and allow slight movement. These are known as partly movable joints.

3. Synovial joints:

These joints are present in the shoulder, hip, knee, ankle, toes, elbow, and the joints of the limbs including the loot fingers.

Their name is derived from the fact sling that they have synovial fluid and is du enclosed within a synovial capsule.

joints allow considerable movement but have ligaments to prevent excessive movement. These are known as movable lee joints.

What are the types of synovial joints?

Synovial joints can be categorized into six types based on the movement they allow. The first type, a plane joint, allows gliding or sliding movement, and the bones involved usually have flat surfaces.

An example of a plane joint is found in the shoulder, between the shoulder blade (acromion of the scapula) and the clavicle.

A hinge joint can move in the axis at a right angle to the joints involved. An example is the elbow joint, which connects the humerus and the ulna.

The movement allowed by this joint includes flexion (bending) and extension (straightening) of your elbow.
The third type of synovial joint is the condyloid joint.

In Greek, “condyloid” means knuckle-like. This type of joint allows movement in two axes. Therefore you can bend it, straighten it, move it from side to side, and rotate it.

An example is your wrist joint. song yen send scrawled The fourth synovial joint type is the saddle joint.

 

 

This joint is so-named because the opposing surfaces of the involved bones look like a saddle-one has a convex surface, while the other has a concave surface.

The thumb joint, which can also move in two axes, is a good example of this joint.

Ball and socket joints are perhaps the most versatile synovial joints. They are multi-axial joints, which means they can move in many axes. One joint has a ball and the other joint has a socket.

The shoulder joint and the hip joints are examples of this type. In the hip joint, the ball is the head of the leg bone (femur) while the socket is the acetabulum of the hip (pelvis).

Try to experiment with the kinds of movement you can make with your hip joint. You can bend, flex, open, close, rotate and circularly move your legs.

These movements of the hip joint are very important for ballerinas and dancers who have complex leg routines.

The last type of synovial joint is the pivot joint. These joints only allow rotation. One bone serves like a ring while the other bone has a rounded process rotating within the ring.

This type is found in your neck, particularly in your first two cervical bones called the atlas (the ring) and the dens (the rounded process). This allows you to rotate your head.

Problems of bone joints:

Joints form the connections between bones. They provide support and help you move. Any damage to the joints from disease or injury can interfere with your movement and cause a lot of pain.

Joint pain can be caused by injury affecting any of the ligaments, bursae, or tendons surrounding the joint. Injury can also affect the ligaments, cartilage, and bones within the joint.

Many different conditions can lead to painful joints including osteoarthritis, rheumatoid arthritis, bursitis, gout, strains, sprains, and other injuries. Joint pain is extremely common.

Joint pain can range from mildly irritating to debilitating. It may go away after a few weeks (acute), or last for several weeks or months (chronic).

Even short-term pain and swelling in the joints can affect your quality of life. Whatever the cause of joint pain, you can usually manage it with medication, physical therapy, or alternative treatments.

3. Muscles

Did you know you have more than 600 muscles in your body? They do everything from pumping blood throughout your body to helping you lift your heavy backpack.

You control some of your muscles, while others–like your heart- do their jobs without you thinking about them at all.

Muscles are all made of the same material, a type of elastic tissue (sort of like the material in a rubber band). Thousands or even tens of thousands of small fibers make up each muscle.

Types of muscles:

You have three different types of muscles in your body: smooth muscle, cardiac muscle, and skeletal muscle.

1. Smooth muscles or Involuntary muscles

Smooth muscles-sometimes also called involuntary muscles-are usually in sheets, or layers, with one layer of muscle behind the other. You cannot control this type of muscle.

Your brain and body tell these muscles what to do without you even thinking about it. But smooth muscles are at work all over your body.

In your stomach and digestive system, they contract (tighten up) and relax to allow food to make its journey through the body. Smooth muscles are also found in your bladder.

When they are relaxed, they allow you to hold in urine until you can get to the bathroom. Then they contract so that you can push the urine out.

2. Cardiac muscles

The muscle that makes up the heart is called cardiac muscle. It is also known as the myocardium. The thick muscles of the heart contract to pump blood out and then relax to let blood in after it has circulated through the body.

Just like smooth muscle, cardiac muscle works all by itself with no help from you. A special group of cells within the heart are known as the pacemaker of the heart because it controls the heartbeat.

3. Straited muscles or Voluntary muscles

Now, let’s talk about the kind of muscle you think of when we say “muscle”-the ones that show how strong you are and let you boot a soccer ball into the goal.

These are your skeletal muscles-sometimes called striated muscles because the light and dark parts of the muscle fibers make them look striped. are voluntary muscles, which means you can control what they do.

Your leg will not bend to kick the soccer ball unless you want it to. These muscles help to make up the musculoskeletal system-the combination of your muscles and your skeleton, or bones.

Skeletal muscles are held to the bones with the help of tendons Tendons are cords made of tough tissue, and they work as special connector pieces between bone and muscle.

The tendons are attached so well that when you contract one of your muscles, the tendon and bone move along with it.

Skeletal muscles also give your body the power it needs to lift and push things. Muscles in your neck and the top part of your back aren’t as large, but they are capable of some pretty amazing things.

Try rotating your head around, back and forth, and up and down to feel the power of the muscles in your neck. These muscles also hold your head high.

How do muscles work? Muscles work by expanding and contracting. Muscles have long, thin cells that are grouped into bundles.

When a muscle fiber gets a signal from its nerve, proteins, and chemicals release energy to either contract the muscle or relax it.

When the muscle contracts, this pulls the bones it’s connected to, closer together. Many of our muscles come in pairs. An example of this is the biceps and triceps in our arms.

When the biceps contract the triceps will relax, which allows our arm to bend. When we want to straighten our arm back out, the biceps will relax and the triceps will contract.

Muscle pairs allow us to move back and forth. Caring muscles Muscles get most of their energy from glucose.

Glucose is made from several types of carbohydrates such as sucrose (which is usually called sugar), lactose (from milk), or fructose (from fruits).

When muscles need to get energy from glucose they do this by changing the glucose into other chemicals such as water and carbon dioxide which release the energy.

We sometimes call this ‘burning’ glucose. They use the oxygen being carried in the blood to help them do this.

Muscles need to move to remain healthy and strong. You can help your muscles stay strong and healthy by exercising every day and using moms have different sets of muscles when they exercise.

When you exercise a lot, your muscles become tired from all the contracting and relaxing. Your muscles might get hurt then.

Have you ever had a cramp? This is when your muscles seem to lock up, and you have a pain in your foot or your leg, or a ‘stitch’ in your side.

This happens when one or more of your muscles contract and will not relax again (called a spasm).

Sweating and not drinking enough on a hot day may mean that you are more likely to get a muscle cramp.
Try drinking water, and stretching and massaging the muscle that hurts and it will get better.

Diseases that can affect muscles: Polio is a virus that attacks the spinal cord. The brain can’t send messages to the muscles and they stop working.

Not long ago a lot of kids would catch this illness, but nowadays not many people get poliomyelitis (that’s its full name) because kids are given an immunization against it.

Tetanus also affects muscles and kids have already had ‘shots’ to stop them from getting this too. There are some other diseases that can affect muscles.

If a person spends long hours in front of a computer then he may sustain injuries from occupational poor posture. The most common such injuries are

1. Mouse shoulder.
2. Computer back
3. Lumbar strains and sprains
4. Disc injuries
5. Tennis elbow.

 

Question 10. Describe the methods of caring for muscles.
Answer:

Bones, Bone-Joints, and Muscles

Every time you move your body from place to place, your bones, muscles, and joints are working together. The bones that make up your skeletal system provide shape and protection.

Your skull protects your brain, your backbones protect your spinal cord and your ribs protect your heart and lungs.

Wherever two bones meet, there is a joint to hold them together and allow them to move, but there would be no movement without the 650 muscles that make up your muscular system.

Bones form the structural framework for our body, while muscles are responsible for pulling the joints, allowing us to move.

The cartilage, muscles, ligaments, and tendons, all work as one, holding bones together and letting joints move. Muscles connect the joints to the bones.

Flexing of the muscles and the ability to bend at the joints moves the bones to accomplish skilled body motions.

1. Bones

Bones make up the framework of our bodies. We call this framework the skeleton. Bones are living, growing, and changing parts of our bodies.

Baby skeletons are made up of more than 300 parts, but by the time we become adults we only have 206 bones. No, we don’t lose any.

It’s just that some of our baby bones are made, partly or completely, of cartilage. As we grow bigger and heavier, cartilage is slowly replaced by harder bone.

Some smaller bones are joined together to make one bigger bone.

Bones are largely made of calcium and other minerals. They are hard enough to support our weight and daily stress. Bones protect our major organs and give our bodies shape.

Bones are actually living tissue. The center of the bone, or marrow, is where your blood is created.

Parts of bones:  Most bones have 4 parts:

1. The outside part of the bone is called the periosteum. This is a thin but very dense layer that has the nerves and blood vessels which nourish the bone.
2.  Compact bone is next. It is smooth and very hard.
3. Cancellous bone comes next and this looks a bit like a sponge but is much stronger.
4. On the very inside of many bones is the bone marrow. It looks a bit like a jelly and it makes new blood cells for the body.

Functions of bones:

1. The bones of the skeleton give us our shape and our posture. Without our spine (backbone) and leg bones, we would be unable to stand erect. Bones also protect the softer parts of our bodies.
2. The skull is like a natural helmet that protects the brain.
3. The spine protects the nerves in the spinal column.
4. The rib makes a shield around our lungs and heart.
5. They act as a base for muscles, ligaments, and tendons. Ligaments connect bones to bones and tendons connect muscles to bones.
6. They all work together to help us move around.

 

 

Different major bony parts of our body

1. Some bones protect the brain. You can feel the bone at the back of your head and forehead.
2. Some bones make the framework for your face. You can feel the bones around your eyes.
3. Some bones in the middle part of your ear carry sound from your eardrum to the inner De ear.
4. You can feel the jawbone under your chin and where it hinges just under your ear. It is the only bone in your skull that you can move.

2. Spine (Vertebral Column)

The spine has 26 bones which are like circles with wings on the sides and back. They are called vertebrae. There are small discs made of cartilage between each vertebra.

They act like shock absorbers and stop the bones from rubbing against each other. There is also a hole through each of the vertebrae where the spinal cord goes.

1. The top 7 are called the cervical vertebrae and they support your head and neck.
2. The next 12 are called the thoracic vertebrae. These hold one end of your ribs.
3. The next 5 are the lumber vertebrae.
4. The next, the sacrum, is a large bone that is actually made of 5 vertebrae fused (joined) together.
5. At the bottom of the spine is the coccyx, which is one bone made of 4 small vertebrae fused together.

 

 

3. Ribs

Ribs make a protective cage around your lungs and heart. There are usually 12 pairs of ribs, each pair attached to the spine at the back.

Each rib is attached to the ribs above and below it by muscles and ligaments.

1. At the front of the body, the top 7 ribs are attached to the sternum (or breast bone).
2. The next 3 pairs are joined to the ribs above and to the sternum, by cartilage.
3. The last 2 pairs of ribs are called the ‘floating’ ribs. They are called floating because they are attached only to the vertebrae and not to the sternum. They don’t have sharp edges sticking out.

4. Arms

Each arm is fastened to the scapula (the shoulder blade) at the back, (which is a triangle-shaped bone near the top of the ribs) and to the clavicle at the front (the collar bone).

The arm has 3 bones-the humerus, the radius, and the ulna. The humerus is the bone between your shoulder and the elbow.

The radius and ulna bones go from the elbow to the wrist. At the end of the radius and ulna is your wrist. Your wrist has 8 small bones, so it is really flexible. In each hand, there are 19 bones.

5. Legs

Your legs are fastened to your pelvis at the hips. The pelvis is shaped like a bowl and supports the contents of your tummy.

1. Legs need to be large and strong to support something to pull them. This job is done by the rest of the body.
2. The femur is the largest bone in the body and it goes from the pelvis to the knee.
3. Another bone called the patella, or kneecap covers the knee joint to protect it.
4. Below the knee, there are 2 bones. These are the tibia and the fibula. They join up to a large bone in the ankle called the talus.
5. There are 6 other bones here so you can move your ankle around but you cannot move it as much as you can move your wrist. Your feet and ankles have a total of 52 bones in them.

 

 

Common orthopedic problems:

Anything that is concerned with muscles, ligaments, and joints is considered orthopedic. Some common problems are

1. Arthritis is a rheumatic disease that has symptoms of pain, limited movement, swelling, and pain in connective tissues.
2. Osteoarthritis is a degenerative joint disease that middle-aged and older adults experience. The joint cartilage breaks down with the progress of your age and it can occur in the hands, knees, spine, or hips.
3. Rheumatoid arthritis is a disease listed in the orthopedic section that causes severe inflammation of the joints. joints. The inflammation is so severe that the functioning of the extremities becomes severely limited.
4. Fractures are definite orthopedic problems.
5. Low back pain is an orthopedic condition that affects one in ten people. Low back pain presents from mild and annoying to persistent and severe.
6. Neck pain can come from injuries or damage to the muscles and ligaments of the neck, a herniated cervical disk of arthritis.

2. Bone Joints

The human body moves in many different ways. You can bend, stretch, turn, and twist. You can move because your bones move at your joints, places where your bones meet.

But your bones can’t move by themselves-they need muscles, which are joined to your bones in order to move them.

There are many joints that help your body move. When you turn your head, bend your knees, or twist your wrists, your joints are in action. Some joints, such as those in your skull, do not move.

These are called fixed joints. Each of the other kinds of joints does a specific type of movement.

What are joints? Joints are places where bones meet. The study of joints is called “arthrology”, which is derived from the Greek words “Atheros” meaning joint, and “logos” meaning study.

One bone can have two or more joints. An example is your jaw or mandible. It is connected to the temporal bones on either side of your skull.

You can feel these joints when you place your hands on the junction of your cheeks and your ears and simulate chewing motions.

What are the functions of your joints:

Aside from smooth movement, joints also have other functions. They allow you to grow. When your brain grows, the sutures in your skull accommodate.

The primary cartilaginous joints of your knees and elbows allow you to grow to your full height. Joints also serve to minimize friction and cushion the bones against impact.

Joints are very important areas in your body. They give you space for growth and allow you to move the way you want.

What are the classifications of joints:

Joints can be classified according to what material unites the bones. The three main types of joints are fibrous joints, cartilaginous joints, and synovial joints.

Fibrous joints are joined by fibrous tissue cartilaginous joints are united by cartilage or a mix of cartilage and fibrous tissue; synovial joints are connected by a synovial membrane that surrounds the joint cavity.

1. Fibrous joints:

The movement allowed by these joints is dependent on the length of the fibrous tissue connecting the bones. In the skull, these joints are called sutures.

Sutures are connected by strong connective tissues and allow very little or no movement in adults. These are known as immovable joints.

 

 

2. Cartilaginous joints:

These joints can be primary cartilaginous joints and secondary cartilaginous joints. Primary cartilaginous joints are connected by cartilage temporarily, early in life.

An example is your knee joint. Later on, the cartilage becomes bone. Secondary cartilaginous joints. consist of bones with the ends covered by cartilage and connected with fibrous. tissue.

These joints are found in the vertebral column and allow slight movement. These are known as partly movable joints.

3. Synovial joints:

These joints are present in the shoulder, hip, knee, ankle, toes, elbow, and the joints of the limbs including the loot fingers.

Their name is derived from the fact sling that they have synovial fluid and is du enclosed within a synovial capsule.

Joints allow considerable movement but have ligaments to prevent excessive movement. These are known as movable lee joints.

What are the types of synovial joints?

Synovial joints can be categorized into six types based on the movement they allow. The first type, a plane joint, allows gliding or sliding movement, and the bones involved usually have flat surfaces.

An example of a plane joint is found in the shoulder, between the shoulder blade (acromion of the scapula) and the clavicle.

A hinge joint can move in the axis at a right angle to the joints involved. An example is the elbow joint, which connects the humerus and the ulna.

The movement allowed by this joint includes flexion (bending) and extension (straightening) of your elbow.
The third type of synovial joint is the condyloid joint.

In Greek, “condyloid” means knuckle-like. This type of joint allows movement in two axes. Therefore you can bend it, straighten it, move it from side to side, and rotate it.

An example is your wrist joint. song yen send scrawled The fourth synovial joint type is the saddle joint.

 

 

This joint is so-named because the opposing surfaces of the involved bones look like a saddle-one has a convex surface, while the other has a concave surface.

The thumb joint, which can also move in two axes, is a good example of this joint.

Ball and socket joints are perhaps the most versatile synovial joints. They are multi-axial joints, which means they can move in many axes. One joint has a ball and the other joint has a socket.

The shoulder joint and the hip joints are examples of this type. In the hip joint, the ball is the head of the leg bone (femur) while the socket is the acetabulum of the hip (pelvis).

Try to experiment with the kinds of movement you can make with your hip joint. You can bend, flex, open, close, rotate and circularly move your legs.

These movements of the hip joint are very important for ballerinas and dancers who have complex leg routines.

The last type of synovial joint is the pivot joint. These joints only allow rotation. One bone serves like a ring while the other bone has a rounded process rotating within the ring.

This type is found in your neck, particularly in your first two cervical bones called the atlas (the ring) and the dens (the rounded process). This allows you to rotate your head.

Problems of bone joints:

Joints form the connections between bones. They provide support and help you move. Any damage to the joints from disease or injury can interfere with your movement and cause a lot of pain.

Joint pain can be caused by injury affecting any of the ligaments, bursae, or tendons surrounding the joint. Injury can also affect the ligaments, cartilage, and bones within the joint.

Many different conditions can lead to painful joints including osteoarthritis, rheumatoid arthritis, bursitis, gout, strains, sprains, and other injuries. Joint pain is extremely common.

Joint pain can range from mildly irritating to debilitating. It may go away after a few weeks (acute), or last for several weeks or months (chronic).

Even short-term pain and swelling in the joints can affect your quality of life. Whatever the cause of joint pain, you can usually manage it with medication, physical therapy, or alternative treatments.

3. Muscles

Did you know you have more than 600 muscles in your body? They do everything from pumping blood throughout your body to helping you lift your heavy backpack.

You control some of your muscles, while others–like your heart- do their jobs without you thinking about them at all.

Muscles are all made of the same material, a type of elastic tissue (sort of like the material in a rubber band). Thousands or even tens of thousands of small fibers make up each muscle.

Types of muscles:

You have three different types of muscles in your body: smooth muscle, cardiac muscle, and skeletal muscle.

1. Smooth muscles or Involuntary muscles

Smooth muscles-sometimes also called involuntary muscles-are usually in sheets, or layers, with one layer of muscle behind the other. You cannot control this type of muscle.

Your brain and body tell these muscles what to do without you even thinking about it. But smooth muscles are at work all over your body.

In your stomach and digestive system, they contract (tighten up) and relax to allow food to make its journey through the body. Smooth muscles are also found in your bladder.

When they are relaxed, they allow you to hold in urine until you can get to the bathroom. Then they contract so that you can push the urine out.

2. Cardiac muscles

The muscle that makes up the heart is called cardiac muscle. It is also known as the myocardium. The thick muscles of the heart contract to pump blood out and then relax to let blood in after it has circulated through the body.

Just like smooth muscle, cardiac muscle works all by itself with no help from you. A special group of cells within the heart are known as the pacemaker of the heart because it controls the heartbeat.

3. Straited muscles or Voluntary muscles

Now, let’s talk about the kind of muscle you think of when we say “muscle”-the ones that show how strong you are and let you boot a soccer ball into the goal.

These are your skeletal muscles-sometimes called striated muscles because the light and dark parts of the muscle fibers make them look striped. are voluntary muscles, which means you can control what they do.

Your leg will not bend to kick the soccer ball unless you want it to. These muscles help to make up the musculoskeletal system-the combination of your muscles and your skeleton, or bones.

Skeletal muscles are held to the bones with the help of tendons Tendons are cords made of tough tissue, and they work as special connector pieces between bone and muscle.

The tendons are attached so well that when you contract one of your muscles, the tendon and bone move along with it.

Skeletal muscles also give your body the power it needs to lift and push things. Muscles in your neck and the top part of your back aren’t as large, but they are capable of some pretty amazing things.

Try rotating your head around, back and forth, and up and down to feel the power of the muscles in your neck. These muscles also hold your head high.

How do muscles work? Muscles work by expanding and contracting. Muscles have long, thin cells that are grouped into bundles.

When a muscle fiber gets a signal from its nerve, proteins, and chemicals release energy to either contract the muscle or relax it.

When the muscle contracts, this pulls the bones it’s connected to, closer together. Many of our muscles come in pairs. An example of this is the biceps and triceps in our arms.

When the biceps contract the triceps will relax, which allows our arm to bend. When we want to straighten our arm back out, the biceps will relax and the triceps will contract.

Muscle pairs allow us to move back and forth. Caring muscles Muscles get most of their energy from glucose.

Glucose is made from several types of carbohydrates such as sucrose (which is usually called sugar), lactose (from milk), or fructose (from fruits).

When muscles need to get energy from glucose they do this by changing the glucose into other chemicals such as water and carbon dioxide which release the energy.

We sometimes call this ‘burning’ glucose. They use the oxygen being carried in the blood to help them do this.

Muscles need to move to remain healthy and strong. You can help your muscles stay strong and healthy by exercising every day and using moms have different sets of muscles when they exercise.

When you exercise a lot, your muscles become tired from all the contracting and relaxing. Your muscles might get hurt then.

Have you ever had a cramp? This is when your muscles seem to lock up, and you have a pain in your foot or your leg, or a ‘stitch’ in your side.

This happens when one or more of your muscles contract and will not relax again (called a spasm).

Sweating and not drinking enough on a hot day may mean that you are more likely to get a muscle cramp.
Try drinking water, and stretching and massaging the muscle that hurts and it will get better.

Diseases that can affect muscles: Polio is a virus that attacks the spinal cord. The brain can’t send messages to the muscles and they stop working.

Not long ago a lot of kids would catch this illness, but nowadays not many people get poliomyelitis (that’s its full name) because kids are given an immunization against it.

Tetanus also affects muscles and kids have already had ‘shots’ to stop them from getting this too. There are some other diseases that can affect muscles.

If a person spends long hours in front of a computer then he may sustain injuries from occupational poor posture. The most common such injuries are

1. Mouse shoulder.
2. Computer back
3. Lumbar strains and sprains
4. Disc injuries
5. Tennis elbow.

 

 

Chapter 8 The Human Body The Growth And Development Of The Human Body Review Questions Environment  Review Questions MCQ

Question 1. Rapid growth occurs during

1. Adulthood
2. Infancy
3. Puberty
4. Old age

Answer: 3. Puberty

Question 2. The head is proportionally large during

1. Childhood
2. Adulthood
3. Old age
4. None are correct

Answer: 1. Childhood

Question 3. When the rate of growth increases rapidly it is called a growth

1. Spurt
2. Age
3. Maximum
4. Final

Answer: 1. Spurt

Question 4. The peak of the growth spurt occurs at about the age of 12 for

1. Boys
2. Human
3. Animals
4. Girls

Answer: 4. Girls

Question 5. The peak of the growth spurt occurs at about the age of 14 for

1. Animals
2. Boys
3. Girls
4. Human

Answer: 2. Boys

Question 6. When a child takes the first step on his or her own, he or she is called a

1. Infant
2. Toddler
3. Teenager
4. Adult

Answer: 2. Toddler

Question 7. With age, children grow both in weight and

1. Maturity
2. Adulthood
3. Height
4. All above are correct

Answer: 3. Height

Question 8. Endocrine glands in our body produce chemical messengers called

1. Hormones
2. Enzymes
3. Food
4. Proteins

Answer: 1. Hormones

Question 9. The pituitary gland produces growth

1. Substances
2. Materials
3. Enzymes
4. Hormones

Answer: 4. Hormones

Question 10. Failure to thrive may happen when a child simply doesn’t get enough to

1. Eat
2. Drink
3. Enjoy
4. Run

Answer: 1. Eat

Question 11. The BMI is defined as the body mass divided by the square of the body

1. Weight
2. Height
3. Growth
4. None of the above

Answer: 2. Height

Question 12. Body mass index is universally expressed in units of

1. Kg/m2
2. Mg/cm
3. G/cm2
4. Height/Weight

Answer: 1. kg/m2

 

Chapter 8 The Human Body The Growth And Development Of The Human Body Fill In The Blanks

Question 1. There are clear stages that children pass through from _________ to adult.
Answer: Birth

Question 2. Children grow in size at a very _________ rate.
Answer: Fast

Question 3. _________ growth occurs during puberty.
Answer: Rapid

Question 4. The _________ proportions of the body at birth are very different from those of the adult.
Answer: Physical

Question 5. When the rate of growth increases rapidly it is called a growth _________.
Answer: Spurt

Question 6. The growth spurt and puberty occur at _________ ages for girls and boys.
Answer: Different

Question 7. Most babies double their birth weight at _________ months.
Answer: 5

Question 8. Glands in our body produce chemical messengers called _________.
Answer: Hormones

Question 9. _________ is the stage of your life when sexual development happens.
Answer: Puberty

Question 10. Growth hormone is produced by _________ gland.
Answer: Pituitary

Question 11. BMI stands for Body Mass _________.
Answer: Index

Question 12. BMI is a crude method to estimate _________.
Answer: Obesity

 

Chapter 8 The Human Body The Growth And Development Of The Human Body Identify As True Or False

Question 1. There are clear stages that children pass through from birth to adulthood.
Answer: True

Question 2. Girls generally mature before boys.
Answer: True

Question 3. At birth, infants are only about half of their adult height.
Answer: False

Question 4. Rapid growth occurs during puberty.
Answer:

Question 5. Rapid slowing down of growth occurs in adolescence until adult height is reached.
Answer: True

Question 6. When the rate of growth decreases rapidly it is called a growth spurt.
Answer: False

Question 7. The growth spurt and puberty occur at different ages for girls and boys.
Answer: True

Question 8. The changes in size and proportion are easily observed signs of development.
Answer: True

Question 9. Everyone grows and matures at the same rate.
Answer: False

Question 10. Hormones play a major role in growth.
Answer: True

 

Chapter 8 The Human Body The Growth And Development Of The Human Body Match The Column

 

Answer: A-2,B-5,C-1,D-3

 

Chapter 8 The Human Body The Growth And Development Of The Human Body Answer in words or a sentence

Question 1. What type of growth occurs during infancy and childhood?
Answer: Rapid growth.

Question 2. When, during growth, legs are proportionately short?
Answer: During Childhood.

Question 3. What is the term used to denote the rate of rapid increase of growth during puberty?
Answer: Growth spurt.

Question 4. What is the period of infancy?
Answer: Birth to 2 years.

Question 5. Who are toddlers?
Answer: Children between the ages of 2-5 years.

Question 6. Name the gland which secretes growth hormone.
Answer: Pituitary gland.

Question 7. What is the full form of FTT?
Answer: Failure to Thrive.

Question 8. What is the full form of BMI?
Answer: Body Mass Index.

 

Chapter 8 The Human Body The Growth And Development Of The Human Body Short Answer Type Questions

Question 1. What is human development?
Answer: Human development is a lifelong process of physical, behavioral, cognitive, and emotional growth and change.

In the early stage of life- from babyhood to childhood, childhood to adolescence, and adolescence to adulthood- enormous changes take place.

Question 2. What is growth?
Answer: Growth refers to a positive change in size, and/ or maturation, often over a period of time. Growth can occur as a stage of maturation or a process toward fullness or fulfillment.

Question 3. What is a growth spurt?
Answer: When the rate of growth increases rapidly it is called a growth spurt. The most important growth spurt is the one that occurs at puberty. This spurt produces a rapid increase in both weight and height.

Question 4. How is the growth spurt of boys and girls different?
Answer: The growth spurt and puberty occur at different ages for girls and boys. Girls usually start and finish the stages of puberty and adolescence earlier than boys.

Question 5. What is psychological development?
Answer: Psychological development is the development of human beings’ cognitive, emotional, intellectual, and social capabilities and functioning over the course of the life span, from infancy through old age.

Question 6. What is adolescence?
Answer: It is the period following the onset of puberty during which a young person develops from a child into an adult.

Question 7. What is meant by growth disorder?
Answer: Growth disorders are problems that prevent children from developing normal height, weight, sexual maturity, or other features.

Question 8. What is BMI?
Answer: The body mass index (BMI) is a value derived from the mass (weight) and height of an Individual. The BMI is defined as the body mass divided by the square of the body height and is universally expressed in units of kg/m2.

Question 9. Calculate the BMI of your friend whose weight and height are 40kg and 4 feet respectively. Answer: What is your inference?
Answer:

BMI=\(\frac{Weight in kg}{(height in m)2}\)

Height = 4 feet = (4×0.305) m1.22 m

Since the BMI falls in the range of 25-29.9, my friend belongs to the overweight category. He should carry out a little bit of exercise to control his body weight in proportion to his height.

 

Chapter 8 The Human Body The Growth And Development Of The Human Body Long Answer Type Questions

Question 1. Write about the patterns of human growth.
Answer:

The Growth And Development Of The Human Body

There are clear stages that children pass through from birth to adulthood. These stages are the same for boys and girls, but girls generally mature before boys. This is clearly shown in the diagram below.

Physical development:

Physical growth is obviously important to performance. We will start by looking at how the body changes during development.

There are important changes in body size and proportions. These changes affect the way where children can perform different skills and activities. our gas Patterns of growth ou mot varans

1. Changes in size

Children grow in size at a very fast rate. At birth, infants are only about a quarter of their adult height.

This final adult height is usually reached at about twenty years of age. There are four characteristic stages of growth from birth to adulthood.

1. Rapid growth in infancy and early childhood
2. Slow, steady growth in middle childhood
3. Rapid growth during puberty bow sort
4. Gradual slowing down of growth in adolescence until adult height is reached. Both sexes are of comparable shape and size during infancy and childhood.

 

 

 

2. Changes in proportions

The physical proportions of the body at birth are very different from those of the adult. Some body parts grow more than others during g development to each of the final adult proportions.

The illustration shows the relative size of body parts at different ages. The head is proportionally large and the legs are proportionally short during childhood.

At birth, the head is one-quarter of the length of the body compared with about one-sixth in the adult. The legs are about one-third the length of the body at birth and one-half in the adult.

Because the body proportions change this means that not all of the body segments grow by the same amount.
Changes in the size and shape of the body. are caused by different segments growing at different times.

These changes in body proportions will have a great influence on how skills will be performed.

 

 

For example, changes in the relative size of the head in childhood affect the balance of the body during movement and the relative shortness of the legs at a very young limit running ability.

At the beginning of puberty, children have long arms and legs. They are better suited for running but the rapid growth may make them appear to be clumsy and to have difficulty in coordination.

Nous Growth spurts:

When the rate of growth increases rapidly it is called a growth spurt. The most important growth spurt is the one that occurs at puberty. This spurt produces a rapid increase in both weight and height.

The peak of this growth spurt occurs at about age 12 for girls and age 14 for boys. Before this growth spurt, there are no important differences between boys and girls in weight and height.

During growth spurts, most of the child’s energy is used for growing.

Children will be easily tired and may not be able to keep up their usual Birth to 1 year to puberty Adolescence growth of trunk growth of legs growth of trunk Areas of growth volume or intensity of training.

Light training will stimulate bodily growth if the child has enough energy.

 

 

 

Difference between boys and girls:

The growth spurt and puberty occur at different ages for girls and boys. Girls usually start and finish the stages of puberty and adolescence earlier than boys.

The characteristic differences between boys and girls occur at puberty in response to changes in hormones produced by shoulders and little change in hip width in boys’ bodies.

Typically, this results in broader and broader hips and little change in shoulder width in girls.

Structure of the body:

The changes in size and proportion are easily observed signs of development. They are the result inside the body of changes to the skeleton.

The skeleton of a child is mostly cartilage, which is softer than bone and can bend. The process by which cartilage becomes bone begins very early in life in special growth areas in the bones.

These special growth areas are called growth plates.

Psychological development:

Children go through distinct periods of development as they move from infants to young adults. During each of these stages, multiple changes in the development of the brain are taking place.

What occurs and approximately when these developments take place are genetically determined.

However, environmental circumstances and exchanges with key individuals within that environment have a significant influence on how each child benefits from each development event.

Ages and stages is a term used to broadly outline key periods in the human development timeline.

During each stage growth and development occur in the primary developmental domains including physical, intellectual, language, and social-emotional.

 

 

1. Infants/Babies (0-2 years)

This is a time for developing the bonds that will last a lifetime providing the child with the inner resources to develop self-esteem and the ability to relate positively with others.

2. Toddlers/Pre-schoolers (2-5 years)

When a child takes the first step on his or her own, a new phase in development begins. At this stage, children are now free to roam around the world.

It is a time for active exploration of their environment.

Language development takes major leaps which leads to learning the names of objects of interest, the ability to ask for things, and as they discover their independent nature.

During this developmental stage, a major challenge is developing what psychologists call emotional regulation.

This is also a stage of rapid physical and intellectual development preparing these children for starting school which includes interacting cooperatively with peers while at the same time being able to compete physically and intellectually.

3. School-age children (6-12 years)

While toddlers and pre-schoolers need constant supervision, school-age children become gradually ready for more independence.

However, learning to make good choices and exercise self-discipline does not come easily for many. Parents need to impart a moral code that the child gradually internalizes.

As children struggle with these important tasks parents must be able to provide praise and encouragement for achievement but parents must also be able to allow them to sometimes experience the natural consequences for their behavior or provide logical consequences to help them learn from mistakes.

4. Adolescents/Teenagers (13-18 years)

It is a time to really begin defining one’s self and realistically contemplating the future. Skill development is accelerated to prepare for college or job training programs.

Talents are perfected. Social skills are honed and relationships take on more of a serious nature. Peer pressure is at its maximum and in today’s teen society there are more tempting sidetracks than ever.

During adolescence, kids need their parents more than ever.

With age, children grow both in weight and height. Their rates of growth are not uniform throughout the whole of childhood.

Growth in the first few years of life is very rapid, and then it slows down later.

Another spurt of growth their birth weight at 5 months and treble it at 1 takes place in adolescence. Most babies have a double year.

While the average length of the baby at birth is about 50 cm (20 inches), it rises to 75 cm (30 inches) at 1 year, i.e., one and a half times more than at birth.

Boys, even in infancy, tend to be taller, heavier and grow faster than girls do. There is a lot of difference in height and weight of children at different ages.

There are also significant variations in the height and weight of children from different regions and communities in a vast and diverse country like India.

The expected average weight and height of Indian children of different ages are given below:

 

 

Abnormal development:

Fairy tales are filled with stories of giants and little people. The stories were written hundreds of years ago, and they sometimes tried to explain why these people looked different from others around them.

These old-fashioned fairy tales might have been different if the writers had known what today’s doctors have learned about growth.

What is Growth Disorder? Everyone grows and matures differently. You may be taller than your best friend in fourth grade. But then in sixth grade, your best friend may be an inch taller than you.

Usually, this is totally normal. A growth disorder, however, means that a kid has abnormal growth-for example, growing a lot slower or a lot faster than other kids at the same age.

What is Normal Growth? If growth is not the same for all kids, how do doctors know what is normal? By feet and inches (or meters and centimeters).

Over the years, lots of height and weight measurements have been taken for lots of children of different ages.

These measurements have been put together in what is called a standard growth chart, which tells doctors about how most kids grow.

From the time you were a baby; your doctor has weighed and measured you whenever you have had a checkup.

Because kids grow differently, your doctor checks your height against the standard growth chart.

If you are in the 50th percentile on the growth chart, it means half of the kids of your age are taller than you are and half are shorter.

If you fall in the 25th percentile that means 75% of the kids of your age are taller and 25% are shorter, and so on.

But some children who are under the 3rd percentile or over the 97th percentile, or who are growing a lot slower or faster than most other kids, may have a growth problem. In this situation, the doctor will usually want to check things out.

One thing your doctor will want to know is how tall your mother and father are and how they grew when they were children.

You may have inherited short or tall genes from them. You may also have inherited the tendency to have your growth spurt earlier or later than most other kids do.

Problems with puberty:

Glands in your body produce chemical messengers called hormones. Normal increases in the amounts of some of these hormones being produced trigger the changes your body goes through during puberty.

Puberty is the stage of your life when sexual development happens, like breast development and menstrual periods in girls and growth of the penis and testicles in boys.

One of the body changes that happen during puberty is a big increase in your rate of growth-a growth spurt.

When these changes happen before the age of 7 or 8 in girls or 9 in boys, it’s called precocious or early puberty.

At first, these kids may be taller than their friends. Later, however, they may stop growing sooner than most other kids do, and they may not become as tall when they are adults as they might have been otherwise.

Usually, kids with precocious puberty can be treated with medications that help correct this problem.

Delayed or late puberty occurs when the hormonal and body changes that should happen with puberty take place later than normal, or sometimes not at all.

Girls who have not begun puberty by age 13 and boys who have not begun by age 15 have delayed puberty and are sometimes called late bloomers.

When puberty finally occurs, either by itself or with treatment, these teens have a growth spurt and tend to catch up to their peers. Sometimes they even grow to be taller than their friends.

Hormones and Growth Disorders:

One of the glands in your body is called the pituitary gland. It’s found at the bottom of your brain and is shaped like a peanut. It may be small in size, but it’s pretty big in importance.

One of the chemical messengers the pituitary gland sends out to your body is called growth hormone, which is essential for growth.

When the pituitary gland doesn’t make enough growth hormone and sometimes other pituitary hormones as well, the condition is called hypopituitarism. This can slow down a kid’s growth.

Special tests can find out if kids don’t produce enough growth hormone. If they don’t, daily shots of growth hormone can often help them grow to be normal-sized adults.

Another gland that produces hormones important for growth is your thyroid. You may be able to feel it if you press gently with your fingers across the front of your neck, just under your Adam’s apple (elevated throat region of males).

It is shaped like a butterfly and moves up and down when you swallow.

Your thyroid makes a hormone called thyroxin. If it makes too little, the condition is called hypothyroidism.

Having too little thyroxin makes a kid grow more slowly. Doctors can do a simple blood test for hypothyroidism. If it’s needed, a kid can take the missing hormone as a pill.

Other reasons why kids might not grow normally:

Hormones play a major role in growth, but kids might not grow normally for other reasons, including:

1. Chronic diseases:

These include heart and kidney problems, cystic fibrosis, juvenile rheumatoid arthritis, and sickle cell anemia, which may slow growth in some cases.

2. Complications during pregnancy:

One of the reasons a pregnant woman is warned not to smoke or drink is because it may slow down her baby’s growth. A baby may be too small when it’s born and some remain small for life.

Some infections during pregnancy, other pregnancy problems, and certain. genetic diseases can also cause this problem.

3. Failure to thrive :

Some babies do not grow and gain weight normally after they are born. This is called failure to thrive (FTT). FTT may happen when a child simply doesn’t get enough to eat.

Some babies may have an illness that needs to be treated, but most will grow normally after they start

4. Genetic conditions:

Some genetics eating enough food. conditions can also cause children to not grow as they should.

Many of these growth disorders can be successfully treated today. With help, kids who might once have ended up very short can grow up more like other children.

Body Mass Index (BMI):

The body mass index (BMI) or Quetelet index is a value derived from the mass (weight) and height of an individual.

The BMI is defined as the body mass divided by the square of the body height and is universally expressed in units of kg/m2, resulting from mass in kilograms and height in meters.

The BMI is an attempt to quantify the amount of tissue mass (muscle, fat, and bone) in an individual, and then categorize that person as underweight, normal weight, overweight, or obese based on that value.

However, there is some debate about where on the BMI scale the dividing lines between categories should be placed.

The body mass index (BMI) is a statistic developed by Adolphe Quetelet in the 1900s for evaluating body mass.

It is not related to gender and age. It used the same formula for men as for women and children.

The body mass index is calculated based on the following formula:

BMI=\(\frac{Weight in Kilograms}{height in Metre2}\)

Example for 175 cm height and 70 kg weight: BMI-70/(1.75 x 1.75) = 22.86

The result is in kilograms by meter square, or kg/m2. BMI is a crude method to estimate obesity. Body Mass Index (BMI) is one of the ways to determine when extra fat accumulates.

Translates into health risks. Body mass index is a measure that takes into account a person’s weight and height to gauge total body fat in adults.

The higher the body mass index, the greater the risk of developing additional health problems. The following chart describes the various categories of obesity based on body mass index.

 

 

BMI < 15 (Excessively low weight)

BMI 16-18 (Low weight)

BMI 19-24.9 (Desirable)

BMI 25-29.9 (Overweight)

BMI30-34.9 (Obese, category 1)

BMI 35-39.9 (Obese, category 2)

BMI > 40 (Severe obesity)

Heart disease, diabetes, and high blood pressure are all linked to being overweight and obese.

Interesting Facts About Human Body

The human body is made up of a head, a neck, a torso (trunk), two arms, and two legs. The average height of an adult human is about 5 to 6 feet.

The human body is made to stand erect, walk on two feet, use the arms to carry and lift, and have opposable thumbs (able to grasp).

The adult body is made up of 100 trillion cells, 206 bones, 650 muscles, and 22 internal organs.

Every square inch of the human body has about 19 million skin cells.

In every hour about 1 billion cells in the human body must be replaced.

The average human head has about 100,000 hairs.

The average adult takes over 20,000 breaths a day.

The circulatory system of arteries, veins, and capillaries is about 60,000 miles long.

The heart beats more than 2.5 billion times in an average lifetime.

There are about 9,000 taste buds on the surface of the tongue, in the throat, and on the roof of the mouth.

The strongest (powerful) muscle in the body is the tongue.

The human heart creates enough pressure when it pumps out to the body to squirt blood bo 30 feet.

You blink over 10,000,000 times a year.

The human brain weighs about 3 pounds.

The brain uses over a quarter of the oxygen used by the human body.

Your heart beats around 100000 times a day, 36500000 times a year, and over a billion times if you live beyond 30.

Red blood cells carry oxygen around the body. They are created inside the bone marrow of your bones.

The color of human skin is determined by the level of pigment melanin that the body produces. Those with a small amount of melanin have light skin while those with a large amount have dark skin.

Adult lungs have a surface area of around 70 square meters.

Humans have a stage of sleep that features rapid eye movement (REM). REM sleep makes up around 25% of total sleep time and is often when you have your most vivid dreams.

Most adults have 32 teeth.

The smallest bone found in the human body is located in the middle ear. The stapes (or stirrup) bone is only 2.8 millimeters long.

Infants blink only once or twice a minute while adults average around 10.

As well as having unique fingerprints, humans also have unique tongue prints.

The left side of your body is controlled by the right side of your brain while the right side of your body is controlled by the left side of your brain.

Antibiotics are only effective against bacteria; they do not help in fighting off a virus.

It takes about 12 hours to completely digest eaten food.

Your sense of smell is around 10000 times more sensitive than your sense of taste.

It takes about 20 seconds for a red blood cell to circle the whole body.

One-fourth of the bones in your body are in your feet.

The blood processing in the kidneys amounts to some 1.25 liters a minute, or 1800 liters a day (1.25 × 60 × 24 = 1800), which is about 400 times the total blood volume and roughly one-fourth the volume pumped each day by the heart.

Every 24 hours, 170 liters of water is filtered from the bloodstream into the renal tubules; and by far the greater part of this- some 168.5 liters of water together with salts dissolved in it is reabsorbed by the cells lining the tubules and returned to the blood.

In a 24-hour period, an average man eliminates only 1.5 liters of water, containing the waste products of metabolism, but the actual volume varies with fluid intake and occupational and environmental factors.

 

Question 2. What is a growth spurt?
Answer:

The Growth And Development Of The Human Body

There are clear stages that children pass through from birth to adulthood. These stages are the same for boys and girls, but girls generally mature before boys. This is clearly shown in the diagram below.

Physical development:

Physical growth is obviously important to performance. We will start by looking at how the body changes during development.

There are important changes in body size and proportions. These changes affect the way where children can perform different skills and activities. our gas Patterns of growth ou mot varans

1. Changes in size

Children grow in size at a very fast rate. At birth, infants are only about a quarter of their adult height.

This final adult height is usually reached at about twenty years of age. There are four characteristic stages of growth from birth to adulthood.

1. Rapid growth in infancy and early childhood
2. Slow, steady growth in middle childhood
3. Rapid growth during puberty bow sort
4. Gradual slowing down of growth in adolescence until adult height is reached. Both sexes are of comparable shape and size during infancy and childhood.

 

 

 

2. Changes in proportions

The physical proportions of the body at birth are very different from those of the adult. Some body parts grow more than others during g development to each of the final adult proportions.

The illustration shows the relative size of body parts at different ages. The head is proportionally large and the legs are proportionally short during childhood.

At birth, the head is one-quarter of the length of the body compared with about one-sixth in the adult. The legs are about one-third the length of the body at birth and one-half in the adult.

Because the body proportions change this means that not all of the body segments grow by the same amount.
Changes in the size and shape of the body. are caused by different segments growing at different times.

These changes in body proportions will have a great influence on how skills will be performed.

 

 

For example, changes in the relative size of the head in childhood affect the balance of the body during movement and the relative shortness of the legs at a very young limit running ability.

At the beginning of puberty, children have long arms and legs. They are better suited for running but the rapid growth may make them appear to be clumsy and to have difficulty in coordination.

Nous Growth spurts:

When the rate of growth increases rapidly it is called a growth spurt. The most important growth spurt is the one that occurs at puberty. This spurt produces a rapid increase in both weight and height.

The peak of this growth spurt occurs at about age 12 for girls and age 14 for boys. Before this growth spurt, there are no important differences between boys and girls in weight and height.

During growth spurts, most of the child’s energy is used for growing.

Children will be easily tired and may not be able to keep up their usual Birth to 1 year to puberty Adolescence growth of trunk growth of legs growth of trunk Areas of growth volume or intensity of training.

Light training will stimulate bodily growth if the child has enough energy.

 

 

 

Difference between boys and girls:

The growth spurt and puberty occur at different ages for girls and boys. Girls usually start and finish the stages of puberty and adolescence earlier than boys.

The characteristic differences between boys and girls occur at puberty in response to changes in hormones produced by shoulders and little change in hip width in boys’ bodies.

Typically, this results in broader and broader hips and little change in shoulder width in girls.

Structure of the body:

The changes in size and proportion are easily observed signs of development. They are the result inside the body of changes to the skeleton.

The skeleton of a child is mostly cartilage, which is softer than bone and can bend. The process by which cartilage becomes bone begins very early in life in special growth areas in the bones.

These special growth areas are called growth plates.

Psychological development:

Children go through distinct periods of development as they move from infants to young adults. During each of these stages, multiple changes in the development of the brain are taking place.

What occurs and approximately when these developments take place are genetically determined.

However, environmental circumstances and exchanges with key individuals within that environment have a significant influence on how each child benefits from each development event.

Ages and stages is a term used to broadly outline key periods in the human development timeline.

During each stage growth and development occur in the primary developmental domains including physical, intellectual, language, and social-emotional.

 

 

1. Infants/Babies (0-2 years)

This is a time for developing the bonds that will last a lifetime providing the child with the inner resources to develop self-esteem and the ability to relate positively with others.

2. Toddlers/Pre-schoolers (2-5 years)

When a child takes the first step on his or her own, a new phase in development begins. At this stage, children are now free to roam around the world.

It is a time for active exploration of their environment.

Language development takes major leaps which leads to learning the names of objects of interest, the ability to ask for things, and as they discover their independent nature.

During this developmental stage, a major challenge is developing what psychologists call emotional regulation.

This is also a stage of rapid physical and intellectual development preparing these children for starting school which includes interacting cooperatively with peers while at the same time being able to compete physically and intellectually.

3. School-age children (6-12 years)

While toddlers and pre-schoolers need constant supervision, school-age children become gradually ready for more independence.

However, learning to make good choices and exercise self-discipline does not come easily for many. Parents need to impart a moral code that the child gradually internalizes.

As children struggle with these important tasks parents must be able to provide praise and encouragement for achievement but parents must also be able to allow them to sometimes experience the natural consequences for their behavior or provide logical consequences to help them learn from mistakes.

4. Adolescents/Teenagers (13-18 years)

It is a time to really begin defining one’s self and realistically contemplating the future. Skill development is accelerated to prepare for college or job training programs.

Talents are perfected. Social skills are honed and relationships take on more of a serious nature. Peer pressure is at its maximum and in today’s teen society there are more tempting sidetracks than ever.

During adolescence, kids need their parents more than ever.

With age, children grow both in weight and height. Their rates of growth are not uniform throughout the whole of childhood.

Growth in the first few years of life is very rapid, and then it slows down later.

Another spurt of growth their birth weight at 5 months and treble it at 1 takes place in adolescence. Most babies have a double year.

While the average length of the baby at birth is about 50 cm (20 inches), it rises to 75 cm (30 inches) at 1 year, i.e., one and a half times more than at birth.

Boys, even in infancy, tend to be taller, heavier and grow faster than girls do. There is a lot of difference in height and weight of children at different ages.

There are also significant variations in the height and weight of children from different regions and communities in a vast and diverse country like India.

The expected average weight and height of Indian children of different ages are given below:

 

 

Abnormal development:

Fairy tales are filled with stories of giants and little people. The stories were written hundreds of years ago, and they sometimes tried to explain why these people looked different from others around them.

These old-fashioned fairy tales might have been different if the writers had known what today’s doctors have learned about growth.

What is Growth Disorder? Everyone grows and matures differently. You may be taller than your best friend in fourth grade. But then in sixth grade, your best friend may be an inch taller than you.

Usually, this is totally normal. A growth disorder, however, means that a kid has abnormal growth-for example, growing a lot slower or a lot faster than other kids at the same age.

What is Normal Growth? If growth is not the same for all kids, how do doctors know what is normal? By feet and inches (or meters and centimeters).

Over the years, lots of height and weight measurements have been taken for lots of children of different ages.

These measurements have been put together in what is called a standard growth chart, which tells doctors about how most kids grow.

From the time you were a baby; your doctor has weighed and measured you whenever you have had a checkup.

Because kids grow differently, your doctor checks your height against the standard growth chart.

If you are in the 50th percentile on the growth chart, it means half of the kids of your age are taller than you are and half are shorter.

If you fall in the 25th percentile that means 75% of the kids of your age are taller and 25% are shorter, and so on.

But some children who are under the 3rd percentile or over the 97th percentile, or who are growing a lot slower or faster than most other kids, may have a growth problem. In this situation, the doctor will usually want to check things out.

One thing your doctor will want to know is how tall your mother and father are and how they grew when they were children.

You may have inherited short or tall genes from them. You may also have inherited the tendency to have your growth spurt earlier or later than most other kids do.

Problems with puberty:

Glands in your body produce chemical messengers called hormones. Normal increases in the amounts of some of these hormones being produced trigger the changes your body goes through during puberty.

Puberty is the stage of your life when sexual development happens, like breast development and menstrual periods in girls and growth of the penis and testicles in boys.

One of the body changes that happen during puberty is a big increase in your rate of growth-a growth spurt.

When these changes happen before the age of 7 or 8 in girls or 9 in boys, it’s called precocious or early puberty.

At first, these kids may be taller than their friends. Later, however, they may stop growing sooner than most other kids do, and they may not become as tall when they are adults as they might have been otherwise.

Usually, kids with precocious puberty can be treated with medications that help correct this problem.

Delayed or late puberty occurs when the hormonal and body changes that should happen with puberty take place later than normal, or sometimes not at all.

Girls who have not begun puberty by age 13 and boys who have not begun by age 15 have delayed puberty and are sometimes called late bloomers.

When puberty finally occurs, either by itself or with treatment, these teens have a growth spurt and tend to catch up to their peers. Sometimes they even grow to be taller than their friends.

Hormones and Growth Disorders:

One of the glands in your body is called the pituitary gland. It’s found at the bottom of your brain and is shaped like a peanut. It may be small in size, but it’s pretty big in importance.

One of the chemical messengers the pituitary gland sends out to your body is called growth hormone, which is essential for growth.

When the pituitary gland doesn’t make enough growth hormone and sometimes other pituitary hormones as well, the condition is called hypopituitarism. This can slow down a kid’s growth.

Special tests can find out if kids don’t produce enough growth hormone. If they don’t, daily shots of growth hormone can often help them grow to be normal-sized adults.

Another gland that produces hormones important for growth is your thyroid. You may be able to feel it if you press gently with your fingers across the front of your neck, just under your Adam’s apple (elevated throat region of males).

It is shaped like a butterfly and moves up and down when you swallow.

Your thyroid makes a hormone called thyroxin. If it makes too little, the condition is called hypothyroidism.

Having too little thyroxin makes a kid grow more slowly. Doctors can do a simple blood test for hypothyroidism. If it’s needed, a kid can take the missing hormone as a pill.

Other reasons why kids might not grow normally:

Hormones play a major role in growth, but kids might not grow normally for other reasons, including

1. Chronic diseases:

These include heart and kidney problems, cystic fibrosis, juvenile rheumatoid arthritis, and sickle cell anemia, which may slow growth in some cases.

2. Complications during pregnancy:

One of the reasons a pregnant woman is warned not to smoke or drink is because it may slow down her baby’s growth. A baby may be too small when it’s born and some remain small for life.

Some infections during pregnancy, other pregnancy problems, and certain. genetic diseases can also cause this problem.

3. Failure to thrive :

Some babies do not grow and gain weight normally after they are born. This is called failure to thrive (FTT). FTT may happen when a child simply doesn’t get enough to eat.

Some babies may have an illness that needs to be treated, but most will grow normally after they start

4. Genetic conditions:

Some genetics eating enough food. conditions can also cause children to not grow as they should.

Many of these growth disorders can be successfully treated today. With help, kids who might once have ended up very short can grow up more like other children.

Body Mass Index (BMI):

The body mass index (BMI) or Quetelet index is a value derived from the mass (weight) and height of an individual.

The BMI is defined as the body mass divided by the square of the body height and is universally expressed in units of kg/m2, resulting from mass in kilograms and height in meters.

The BMI is an attempt to quantify the amount of tissue mass (muscle, fat, and bone) in an individual, and then categorize that person as underweight, normal weight, overweight, or obese based on that value.

However, there is some debate about where on the BMI scale the dividing lines between categories should be placed.

The body mass index (BMI) is a statistic developed by Adolphe Quetelet in the 1900s for evaluating body mass.

It is not related to gender and age. It used the same formula for men as for women and children.

The body mass index is calculated based on the following formula:

BMI=\(\frac{Weight in Kilograms}{height in Metre2}\)

Example for 175 cm height and 70 kg weight: BMI-70/(1.75 x 1.75) = 22.86

The result is in kilograms by meter square, or kg/m2. BMI is a crude method to estimate obesity. Body Mass Index (BMI) is one of the ways to determine when extra fat accumulates.

translates into health risks. Body mass index is a measure that takes into account a person’s weight and height to gauge total body fat in adults.

The higher the body mass index, the greater the risk of developing additional health problems. The following chart describes the various categories of obesity based on body mass index

 

 

BMI < 15 (Excessively low weight)

BMI 16-18 (Low weight)

BMI 19-24.9 (Desirable)

BMI 25-29.9 (Overweight)

BMI30-34.9 (Obese, category 1)

BMI 35-39.9 (Obese, category 2)

BMI > 40 (Severe obesity)

Heart disease, diabetes, and high blood pressure are all linked to being overweight and obese.

Interesting Facts About Human Body

The human body is made up of a head, a neck, a torso (trunk), two arms, and two legs. The average height of an adult human is about 5 to 6 feet.

The human body is made to stand erect, walk on two feet, use the arms to carry and lift, and have opposable thumbs (able to grasp).

The adult body is made up of 100 trillion cells, 206 bones, 650 muscles, and 22 internal organs.

Every square inch of the human body has about 19 million skin cells.

In every hour about 1 billion cells in the human body must be replaced.

The average human head has about 100,000 hairs.

The average adult takes over 20,000 breaths a day.

The circulatory system of arteries, veins, and capillaries is about 60,000 miles long.

The heart beats more than 2.5 billion times in an average lifetime.

There are about 9,000 taste buds on the surface of the tongue, in the throat, and on the roof of the mouth.

The strongest (powerful) muscle in the body is the tongue.

The human heart creates enough pressure when it pumps out to the body to squirt blood bo 30 feet.

You blink over 10,000,000 times a year.

The human brain weighs about 3 pounds.

The brain uses over a quarter of the oxygen used by the human body.

Your heart beats around 100000 times a day, 36500000 times a year, and over a billion times if you live beyond 30.

Red blood cells carry oxygen around the body. They are created inside the bone marrow of your bones.

The color of human skin is determined by the level of pigment melanin that the body produces. Those with a small amount of melanin have light skin while those with a large amount have dark skin.

Adult lungs have a surface area of around 70 square meters.

Humans have a stage of sleep that features rapid eye movement (REM). REM sleep makes up around 25% of total sleep time and is often when you have your most vivid dreams.

Most adults have 32 teeth.

The smallest bone found in the human body is located in the middle ear. The stapes (or stirrup) bone is only 2.8 millimeters long.

Infants blink only once or twice a minute while adults average around 10.

As well as having unique fingerprints, humans also have unique tongue prints.

The left side of your body is controlled by the right side of your brain while the right side of your body is controlled by the left side of your brain.

Antibiotics are only effective against bacteria; they do not help in fighting off a virus.

It takes about 12 hours to completely digest eaten food.

Your sense of smell is around 10000 times more sensitive than your sense of taste.

It takes about 20 seconds for a red blood cell to circle the whole body.

One-fourth of the bones in your body are in your feet.

The blood processing in the kidneys amounts to some 1.25 liters a minute, or 1800 liters a day (1.25 × 60 × 24 = 1800), which is about 400 times the total blood volume and roughly one-fourth the volume pumped each day by the heart.

Every 24 hours, 170 liters of water is filtered from the bloodstream into the renal tubules; and by far the greater part of this- some 168.5 liters of water together with salts dissolved in it is reabsorbed by the cells lining the tubules and returned to the blood.

In a 24-hour period, an average man eliminates only 1.5 liters of water, containing the waste products of metabolism, but the actual volume varies with fluid intake and occupational and environmental factors.

 

Question 3. Write about the change during adolescence.
Answer:

The Growth And Development Of The Human Body

There are clear stages that children pass through from birth to adulthood. These stages are the same for boys and girls, but girls generally mature before boys. This is clearly shown in the diagram below.

Physical development:

Physical growth is obviously important to performance. We will start by looking at how the body changes during development.

There are important changes in body size and proportions. These changes affect the way where children can perform different skills and activities. our gas Patterns of growth ou mot varans

1. Changes in size

Children grow in size at a very fast rate. At birth, infants are only about a quarter of their adult height.

This final adult height is usually reached at about twenty years of age. There are four characteristic stages of growth from birth to adulthood.

1. Rapid growth in infancy and early childhood
2. Slow, steady growth in middle childhood
3. Rapid growth during puberty bow sort
4. Gradual slowing down of growth in adolescence until adult height is reached. Both sexes are of comparable shape and size during infancy and childhood.

 

 

 

2. Changes in proportions

The physical proportions of the body at birth are very different from those of the adult. Some body parts grow more than others during g development to each of the final adult proportions.

The illustration shows the relative size of body parts at different ages. The head is proportionally large and the legs are proportionally short during childhood.

At birth, the head is one-quarter of the length of the body compared with about one-sixth in the adult. The legs are about one-third the length of the body at birth and one-half in the adult.

Because the body proportions change this means that not all of the body segments grow by the same amount.
Changes in the size and shape of the body. are caused by different segments growing at different times.

These changes in body proportions will have a great influence on how skills will be performed.

 

 

For example, changes in the relative size of the head in childhood affect the balance of the body during movement and the relative shortness of the legs at a very young limits running ability.

At the beginning of puberty, children have long arms and legs. They are better suited for running but the rapid growth may make them appear to be clumsy and to have difficulty in coordination.

Nous Growth spurts:

When the rate of growth increases rapidly it is called a growth spurt. The most important growth spurt is the one that occurs at puberty. This spurt produces a rapid increase in both weight and height.

The peak of this growth spurt occurs at about age 12 for girls and age 14 for boys. Before this growth spurt, there are no important differences between boys and girls in weight and height.

During growth spurts, most of the child’s energy is used for growing.

Children will be easily tired and may not be able to keep up their usual Birth to 1 year to puberty Adolescence growth of trunk growth of legs growth of trunk Areas of growth volume or intensity of training.

Light training will stimulate bodily growth if the child has enough energy.

 

 

 

Difference between boys and girls:

The growth spurt and puberty occur at different ages for girls and boys. Girls usually start and finish the stages of puberty and adolescence earlier than boys.

The characteristic differences between boys and girls occur at puberty in response to changes in hormones produced by shoulders and little change in hip width in boys’ bodies.

Typically, this results in broader and broader hips and little change in shoulder width in girls.

Structure of the body:

The changes in size and proportion are easily observed signs of development. They are the result inside the body of changes to the skeleton.

The skeleton of a child is mostly cartilage, which is softer than bone and can bend. The process by which cartilage becomes bone begins very early in life in special growth areas in the bones.

These special growth areas are called growth plates.

Psychological development:

Children go through distinct periods of development as they move from infants to young adults. During each of these stages, multiple changes in the development of the brain are taking place.

What occurs and approximately when these developments take place are genetically determined.

However, environmental circumstances and exchanges with key individuals within that environment have a significant influence on how each child benefits from each development event.

Ages and stages is a term used to broadly outline key periods in the human development timeline.

During each stage growth and development occur in the primary developmental domains including physical, intellectual, language, and social-emotional.

 

 

1. Infants/Babies (0-2 years)

This is a time for developing the bonds that will last a lifetime providing the child with the inner resources to develop self-esteem and the ability to relate positively with others.

2. Toddlers/Pre-schoolers (2-5 years)

When a child takes the first step on his or her own, a new phase in development begins. At this stage, children are now free to roam around the world.

It is a time for active exploration of their environment.

Language development takes major leaps which leads to learning the names of objects of interest, the ability to ask for things, and as they discover their independent nature.

During this developmental stage, a major challenge is developing what psychologists call emotional regulation.

This is also a stage of rapid physical and intellectual development preparing these children for starting school which includes interacting cooperatively with peers while at the same time being able to compete physically and intellectually.

3. School-age children (6-12 years)

While toddlers and pre-schoolers need constant supervision, school-age children become gradually ready for more independence.

However, learning to make good choices and exercise self-discipline does not come easily for many. Parents need to impart a moral code that the child gradually internalizes.

As children struggle with these important tasks parents must be able to provide praise and encouragement for achievement but parents must also be able to allow them to sometimes experience the natural consequences for their behavior or provide logical consequences to help them learn from mistakes.

4. Adolescents/Teenagers (13-18 years)

It is a time to really begin defining one’s self and realistically contemplating the future. Skill development is accelerated to prepare for college or job training programs.

Talents are perfected. Social skills are honed and relationships take on more of a serious nature. Peer pressure is at its maximum and in today’s teen society there are more tempting sidetracks than ever.

During adolescence, kids need their parents more than ever.

With age, children grow both in weight and height. Their rates of growth are not uniform throughout the whole of childhood.

Growth in the first few years of life is very rapid, and then it slows down later.

Another spurt of growth their birth weight at 5 months and treble it at 1 takes place in adolescence. Most babies have a double year.

While the average length of the baby at birth is about 50 cm (20 inches), it rises to 75 cm (30 inches) at 1 year, i.e., one and a half times more than at birth.

Boys, even in infancy, tend to be taller, heavier and grow faster than girls do. There is a lot of difference in height and weight of children at different ages.

There are also significant variations in the height and weight of children from different regions and communities in a vast and diverse country like India.

The expected average weight and height of Indian children of different ages are given below:

 

 

Abnormal development:

Fairy tales are filled with stories of giants and little people. The stories were written hundreds of years ago, and they sometimes tried to explain why these people looked different from others around them.

These old-fashioned fairy tales might have been different if the writers had known what today’s doctors have learned about growth.

What is Growth Disorder? Everyone grows and matures differently. You may be taller than your best friend in fourth grade. But then in sixth grade, your best friend may be an inch taller than you.

Usually, this is totally normal. A growth disorder, however, means that a kid has abnormal growth-for example, growing a lot slower or a lot faster than other kids at the same age.

What is Normal Growth? If growth is not the same for all kids, how do doctors know what is normal? By feet and inches (or meters and centimeters).

Over the years, lots of height and weight measurements have been taken for lots of children of different ages.

These measurements have been put together in what is called a standard growth chart, which tells doctors about how most kids grow.

From the time you were a baby; your doctor has weighed and measured you whenever you have had a checkup.

Because kids grow differently, your doctor checks your height against the standard growth chart.

If you are in the 50th percentile on the growth chart, it means half of the kids of your age are taller than you are and half are shorter.

If you fall in the 25th percentile that means 75% of the kids of your age are taller and 25% are shorter, and so on.

But some children who are under the 3rd percentile or over the 97th percentile, or who are growing a lot slower or faster than most other kids, may have a growth problem. In this situation, the doctor will usually want to check things out.

One thing your doctor will want to know is how tall your mother and father are and how they grew when they were children.

You may have inherited short or tall genes from them. You may also have inherited the tendency to have your growth spurt earlier or later than most other kids do.

Problems with puberty:

Glands in your body produce chemical messengers called hormones. Normal increases in the amounts of some of these hormones being produced trigger the changes your body goes through during puberty.

Puberty is the stage of your life when sexual development happens, like breast development and menstrual periods in girls and growth of the penis and testicles in boys.

One of the body changes that happen during puberty is a big increase in your rate of growth-a growth spurt.

When these changes happen before the age of 7 or 8 in girls or 9 in boys, it’s called precocious or early puberty.

At first, these kids may be taller than their friends. Later, however, they may stop growing sooner than most other kids do, and they may not become as tall when they are adults as they might have been otherwise.

Usually, kids with precocious puberty can be treated with medications that help correct this problem.

Delayed or late puberty occurs when the hormonal and body changes that should happen with puberty take place later than normal, or sometimes not at all.

Girls who have not begun puberty by age 13 and boys who have not begun by age 15 have delayed puberty and are sometimes called late bloomers.

When puberty finally occurs, either by itself or with treatment, these teens have a growth spurt and tend to catch up to their peers. Sometimes they even grow to be taller than their friends.

Hormones and Growth Disorders:

One of the glands in your body is called the pituitary gland. It’s found at the bottom of your brain and is shaped like a peanut. It may be small in size, but it’s pretty big in importance.

One of the chemical messengers the pituitary gland sends out to your body is called growth hormone, which is essential for growth.

When the pituitary gland doesn’t make enough growth hormone and sometimes other pituitary hormones as well, the condition is called hypopituitarism. This can slow down a kid’s growth.

Special tests can find out if kids don’t produce enough growth hormone. If they don’t, daily shots of growth hormone can often help them grow to be normal-sized adults.

Another gland that produces hormones important for growth is your thyroid. You may be able to feel it if you press gently with your fingers across the front of your neck, just under your Adam’s apple (elevated throat region of males).

It is shaped like a butterfly and moves up and down when you swallow.

Your thyroid makes a hormone called thyroxin. If it makes too little, the condition is called hypothyroidism.

Having too little thyroxin makes a kid grow more slowly. Doctors can do a simple blood test for hypothyroidism. If it’s needed, a kid can take the missing hormone as a pill.

Other reasons why kids might not grow normally:

Hormones play a major role in growth, but kids might not grow normally for other reasons, including:

1. Chronic diseases:

These include heart and kidney problems, cystic fibrosis, juvenile rheumatoid arthritis, and sickle cell anemia, which may slow growth in some cases.

2. Complications during pregnancy:

One of the reasons a pregnant woman is warned not to smoke or drink is because it may slow down her baby’s growth. A baby may be too small when it’s born and some remain small for life.

Some infections during pregnancy, other pregnancy problems, and certain. genetic diseases can also cause this problem.

3. Failure to thrive :

Some babies do not grow and gain weight normally after they are born. This is called failure to thrive (FTT). FTT may happen when a child simply doesn’t get enough to eat.

Some babies may have an illness that needs to be treated, but most will grow normally after they start

4. Genetic conditions:

Some genetics eating enough food. conditions can also cause children to not grow as they should.

Many of these growth disorders can be successfully treated today. With help, kids who might once have ended up very short can grow up more like other children.

Body Mass Index (BMI):

The body mass index (BMI) or Quetelet index is a value derived from the mass (weight) and height of an individual.

The BMI is defined as the body mass divided by the square of the body height and is universally expressed in units of kg/m2, resulting from mass in kilograms and height in meters.

The BMI is an attempt to quantify the amount of tissue mass (muscle, fat, and bone) in an individual, and then categorize that person as underweight, normal weight, overweight, or obese based on that value.

However, there is some debate about where on the BMI scale the dividing lines between categories should be placed.

The body mass index (BMI) is a statistic developed by Adolphe Quetelet in the 1900s for evaluating body mass.

It is not related to gender and age. It used the same formula for men as for women and children.

The body mass index is calculated based on the following formula:

BMI=\(\frac{Weight in Kilograms}{height in Metre2}\)

Example for 175 cm height and 70 kg weight: BMI-70/(1.75 x 1.75) = 22.86

The result is in kilograms by meter square, or kg/m2. BMI is a crude method to estimate obesity. Body Mass Index (BMI) is one of the ways to determine when extra fat accumulates.

Translates into health risks. Body mass index is a measure that takes into account a person’s weight and height to gauge total body fat in adults.

The higher the body mass index, the greater the risk of developing additional health problems. The following chart describes the various categories of obesity based on body mass index

 

 

BMI < 15 (Excessively low weight)

BMI 16-18 (Low weight)

BMI 19-24.9 (Desirable)

BMI 25-29.9 (Overweight)

BMI30-34.9 (Obese, category 1)

BMI 35-39.9 (Obese, category 2)

BMI > 40 (Severe obesity)

Heart disease, diabetes, and high blood pressure are all linked to being overweight and obese.

Interesting Facts About Human Body

The human body is made up of a head, a neck, a torso (trunk), two arms, and two legs. The average height of an adult human is about 5 to 6 feet.

The human body is made to stand erect, walk on two feet, use the arms to carry and lift, and have opposable thumbs (able to grasp).

The adult body is made up of 100 trillion cells, 206 bones, 650 muscles, and 22 internal organs.

Every square inch of the human body has about 19 million skin cells.

In every hour about 1 billion cells in the human body must be replaced.

The average human head has about 100,000 hairs.

The average adult takes over 20,000 breaths a day.

The circulatory system of arteries, veins, and capillaries is about 60,000 miles long.

The heart beats more than 2.5 billion times in an average lifetime.

There are about 9,000 taste buds on the surface of the tongue, in the throat, and on the roof of the mouth.

The strongest (powerful) muscle in the body is the tongue.

The human heart creates enough pressure when it pumps out to the body to squirt blood bo 30 feet.

You blink over 10,000,000 times a year.

The human brain weighs about 3 pounds.

The brain uses over a quarter of the oxygen used by the human body.

Your heart beats around 100000 times a day, 36500000 times a year, and over a billion times if you live beyond 30.

Red blood cells carry oxygen around the body. They are created inside the bone marrow of your bones.

The color of human skin is determined by the level of pigment melanin that the body produces. Those with a small amount of melanin have light skin while those with a large amount have dark skin.

Adult lungs have a surface area of around 70 square meters.

Humans have a stage of sleep that features rapid eye movement (REM). REM sleep makes up around 25% of total sleep time and is often when you have your most vivid dreams.

Most adults have 32 teeth.

The smallest bone found in the human body is located in the middle ear. The stapes (or stirrup) bone is only 2.8 millimeters long.

Infants blink only once or twice a minute while adults average around 10.

As well as having unique fingerprints, humans also have unique tongue prints.

The left side of your body is controlled by the right side of your brain while the right side of your body is controlled by the left side of your brain.

Antibiotics are only effective against bacteria; they do not help in fighting off a virus.

It takes about 12 hours to completely digest eaten food.

Your sense of smell is around 10000 times more sensitive than your sense of taste.

It takes about 20 seconds for a red blood cell to circle the whole body.

One-fourth of the bones in your body are in your feet.

The blood processing in the kidneys amounts to some 1.25 liters a minute, or 1800 liters a day (1.25 × 60 × 24 = 1800), which is about 400 times the total blood volume and roughly one-fourth the volume pumped each day by the heart.

Every 24 hours, 170 liters of water is filtered from the bloodstream into the renal tubules; and by far the greater part of this- some 168.5 liters of water together with salts dissolved in it is reabsorbed by the cells lining the tubules and returned to the blood.

In a 24-hour period, an average man eliminates only 1.5 liters of water, containing the waste products of metabolism, but the actual volume varies with fluid intake and occupational and environmental factors.

 

Question 4. Briefly describe human growth disorders.
Answer:

Hormones and Growth Disorders:

One of the glands in your body is called the pituitary gland. It’s found at the bottom of your brain and is shaped like a peanut. It may be small in size, but it’s pretty big in importance.

One of the chemical messengers the pituitary gland sends out to your body is called growth hormone, which is essential for growth.

When the pituitary gland doesn’t make enough growth hormone and sometimes other pituitary hormones as well, the condition is called hypopituitarism. This can slow down a kid’s growth.

Special tests can find out if kids don’t produce enough growth hormone. If they don’t, daily shots of growth hormone can often help them grow to be normal-sized adults.

Another gland that produces hormones important for growth is your thyroid. You may be able to feel it if you press gently with your fingers across the front of your neck, just under your Adam’s apple (elevated throat region of males).

It is shaped like a butterfly and moves up and down when you swallow.

Your thyroid makes a hormone called thyroxin. If it makes too little, the condition is called hypothyroidism.

Having too little thyroxin makes a kid grow more slowly. Doctors can do a simple blood test for hypothyroidism. If it’s needed, a kid can take the missing hormone as a pill.

Other reasons why kids might not grow normally:

Hormones play a major role in growth, but kids might not grow normally for other reasons, including:

1. Chronic diseases:

These include heart and kidney problems, cystic fibrosis, juvenile rheumatoid arthritis, and sickle cell anemia, which may slow growth in some cases.

2. Complications during pregnancy:

One of the reasons a pregnant woman is warned not to smoke or drink is because it may slow down her baby’s growth. A baby may be too small when it’s born and some remain small for life.

Some infections during pregnancy, other pregnancy problems, and certain. genetic diseases can also cause this problem.

3. Failure to thrive :

Some babies do not grow and gain weight normally after they are born. This is called failure to thrive (FTT). FTT may happen when a child simply doesn’t get enough to eat.

Some babies may have an illness that needs to be treated, but most will grow normally after they start

4. Genetic conditions:

Some genetics eating enough food. conditions can also cause children to not grow as they should.

Many of these growth disorders can be successfully treated today. With help, kids who might once have ended up very short can grow up more like other children.

Body Mass Index (BMI):

The body mass index (BMI) or Quetelet index is a value derived from the mass (weight) and height of an individual.

The BMI is defined as the body mass divided by the square of the body height and is universally expressed in units of kg/m2, resulting from mass in kilograms and height in meters.

The BMI is an attempt to quantify the amount of tissue mass (muscle, fat, and bone) in an individual, and then categorize that person as underweight, normal weight, overweight, or obese based on that value.

However, there is some debate about where on the BMI scale the dividing lines between categories should be placed.

The body mass index (BMI) is a statistic developed by Adolphe Quetelet in the 1900s for evaluating body mass.

It is not related to gender and age. It used the same formula for men as for women and children.

The body mass index is calculated based on the following formula:

BMI=\(\frac{Weight in Kilograms}{height in Metre2}\)

Example for 175 cm height and 70 kg weight: BMI-70/(1.75 x 1.75) = 22.86

The result is in kilograms by meter square, or kg/m2. BMI is a crude method to estimate obesity. Body Mass Index (BMI) is one of the ways to determine when extra fat accumulates.

translates into health risks. Body mass index is a measure that takes into account a person’s weight and height to gauge total body fat in adults.

The higher the body mass index, the greater the risk of developing additional health problems. The following chart describes the various categories of obesity based on body mass index.

 

Question 5. What is BMI? The height and weight of a person are 1.5 m and 50 kg respectively. Calculate the BMI of that person. Find out if the person is desirable or obese.
Answer:

The Growth And Development Of The Human Body

There are clear stages that children pass through from birth to adulthood. These stages are the same for boys and girls, but girls generally mature before boys. This is clearly shown in the diagram below.

Physical development:

Physical growth is obviously important to performance. We will start by looking at how the body changes during development.

There are important changes in body size and proportions. These changes affect the way where children can perform different skills and activities. our gas Patterns of growth ou mot varans

1. Changes in size

Children grow in size at a very fast rate. At birth, infants are only about a quarter of their adult height.

This final adult height is usually reached at about twenty years of age. There are four characteristic stages of growth from birth to adulthood.

1. Rapid growth in infancy and early childhood
2. Slow, steady growth in middle childhood
3. Rapid growth during puberty bow sort
4. Gradual slowing down of growth in adolescence until adult height is reached. Both sexes are of comparable shape and size during infancy and childhood.

 

 

 

2. Changes in proportions

The physical proportions of the body at birth are very different from those of the adult. Some body parts grow more than others during g development to each of the final adult proportions.

The illustration shows the relative size of body parts at different ages. The head is proportionally large and the legs are proportionally short during childhood.

At birth, the head is one-quarter of the length of the body compared with about one-sixth in the adult. The legs are about one-third the length of the body at birth and one-half in the adult.

Because the body proportions change this means that not all of the body segments grow by the same amount.
Changes in the size and shape of the body. are caused by different segments growing at different times.

These changes in body proportions will have a great influence on how skills will be performed.

 

 

For example, changes in the relative size of the head in childhood affect the balance of the body during movement and the relative shortness of the legs at a very young limit running ability.

At the beginning of puberty, children have long arms and legs. They are better suited for running but the rapid growth may make them appear to be clumsy and to have difficulty in coordination.

Nous Growth spurts:

When the rate of growth increases rapidly it is called a growth spurt. The most important growth spurt is the one that occurs at puberty. This spurt produces a rapid increase in both weight and height.

The peak of this growth spurt occurs at about age 12 for girls and age 14 for boys. Before this growth spurt, there are no important differences between boys and girls in weight and height.

During growth spurts, most of the child’s energy is used for growing.

Children will be easily tired and may not be able to keep up their usual Birth to 1 year to puberty Adolescence growth of trunk growth of legs growth of trunk Areas of growth volume or intensity of training.

Light training will stimulate bodily growth if the child has enough energy.

 

 

 

Difference between boys and girls:

The growth spurt and puberty occur at different ages for girls and boys. Girls usually start and finish the stages of puberty and adolescence earlier than boys.

The characteristic differences between boys and girls occur at puberty in response to changes in hormones produced by shoulders and little change in hip width in boys’ bodies.

Typically, this results in broader and broader hips and little change in shoulder width in girls.

Structure of the body:

The changes in size and proportion are easily observed signs of development. They are the result inside the body of changes to the skeleton.

The skeleton of a child is mostly cartilage, which is softer than bone and can bend. The process by which cartilage becomes bone begins very early in life in special growth areas in the bones.

These special growth areas are called growth plates.

Psychological development:

Children go through distinct periods of development as they move from infants to young adults. During each of these stages, multiple changes in the development of the brain are taking place.

What occurs and approximately when these developments take place are genetically determined.

However, environmental circumstances and exchanges with key individuals within that environment have a significant influence on how each child benefits from each development event.

Ages and stages is a term used to broadly outline key periods in the human development timeline.

During each stage growth and development occur in the primary developmental domains including physical, intellectual, language, and social-emotional.

 

 

1. Infants/Babies (0-2 years)

This is a time for developing the bonds that will last a lifetime providing the child with the inner resources to develop self-esteem and the ability to relate positively with others.

2. Toddlers/Pre-schoolers (2-5 years)

When a child takes the first step on his or her own, a new phase in development begins. At this stage, children are now free to roam around the world.

It is a time for active exploration of their environment.

Language development takes major leaps which leads to learning the names of objects of interest, the ability to ask for things, and as they discover their independent nature.

During this developmental stage, a major challenge is developing what psychologists call emotional regulation.

This is also a stage of rapid physical and intellectual development preparing these children for starting school which includes interacting cooperatively with peers while at the same time being able to compete physically and intellectually.

3. School-age children (6-12 years)

While toddlers and pre-schoolers need constant supervision, school-age children become gradually ready for more independence.

However, learning to make good choices and exercise self-discipline does not come easily for many. Parents need to impart a moral code that the child gradually internalizes.

As children struggle with these important tasks parents must be able to provide praise and encouragement for achievement but parents must also be able to allow them to sometimes experience the natural consequences for their behavior or provide logical consequences to help them learn from mistakes.

4. Adolescents/Teenagers (13-18 years)

It is a time to really begin defining one’s self and realistically contemplating the future. Skill development is accelerated to prepare for college or job training programs.

Talents are perfected. Social skills are honed and relationships take on more of a serious nature. Peer pressure is at its maximum and in today’s teen society there are more tempting sidetracks than ever.

During adolescence, kids need their parents more than ever.

With age, children grow both in weight and height. Their rates of growth are not uniform throughout the whole of childhood.

Growth in the first few years of life is very rapid, and then it slows down later.

Another spurt of growth their birth weight at 5 months and treble it at 1 takes place in adolescence. Most babies have a double year.

While the average length of the baby at birth is about 50 cm (20 inches), it rises to 75 cm (30 inches) at 1 year, i.e., one and a half times more than at birth.

Boys, even in infancy, tend to be taller, heavier and grow faster than girls do. There is a lot of difference in height and weight of children at different ages.

There are also significant variations in the height and weight of children from different regions and communities in a vast and diverse country like India.

The expected average weight and height of Indian children of different ages are given below:

 

 

Abnormal development:

Fairy tales are filled with stories of giants and little people. The stories were written hundreds of years ago, and they sometimes tried to explain why these people looked different from others around them.

These old-fashioned fairy tales might have been different if the writers had known what today’s doctors have learned about growth.

What is Growth Disorder? Everyone grows and matures differently. You may be taller than your best friend in fourth grade. But then in sixth grade, your best friend may be an inch taller than you.

Usually, this is totally normal. A growth disorder, however, means that a kid has abnormal growth-for example, growing a lot slower or a lot faster than other kids at the same age.

What is Normal Growth? If growth is not the same for all kids, how do doctors know what is normal? By feet and inches (or meters and centimeters).

Over the years, lots of height and weight measurements have been taken for lots of children of different ages.

These measurements have been put together in what is called a standard growth chart, which tells doctors about how most kids grow.

From the time you were a baby; your doctor has weighed and measured you whenever you have had a checkup.

Because kids grow differently, your doctor checks your height against the standard growth chart.

If you are in the 50th percentile on the growth chart, it means half of the kids of your age are taller than you are and half are shorter.

If you fall in the 25th percentile that means 75% of the kids of your age are taller and 25% are shorter, and so on.

But some children who are under the 3rd percentile or over the 97th percentile, or who are growing a lot slower or faster than most other kids, may have a growth problem. In this situation, the doctor will usually want to check things out.

One thing your doctor will want to know is how tall your mother and father are and how they grew when they were children.

You may have inherited short or tall genes from them. You may also have inherited the tendency to have your growth spurt earlier or later than most other kids do.

Problems with puberty:

Glands in your body produce chemical messengers called hormones. Normal increases in the amounts of some of these hormones being produced trigger the changes your body goes through during puberty.

Puberty is the stage of your life when sexual development happens, like breast development and menstrual periods in girls and growth of the penis and testicles in boys.

One of the body changes that happen during puberty is a big increase in your rate of growth-a growth spurt.

When these changes happen before the age of 7 or 8 in girls or 9 in boys, it’s called precocious or early puberty.

At first, these kids may be taller than their friends. Later, however, they may stop growing sooner than most other kids do, and they may not become as tall when they are adults as they might have been otherwise.

Usually, kids with precocious puberty can be treated with medications that help correct this problem.

Delayed or late puberty occurs when the hormonal and body changes that should happen with puberty take place later than normal, or sometimes not at all.

Girls who have not begun puberty by age 13 and boys who have not begun by age 15 have delayed puberty and are sometimes called late bloomers.

When puberty finally occurs, either by itself or with treatment, these teens have a growth spurt and tend to catch up to their peers. Sometimes they even grow to be taller than their friends.

Hormones and Growth Disorders:

One of the glands in your body is called the pituitary gland. It’s found at the bottom of your brain and is shaped like a peanut. It may be small in size, but it’s pretty big in importance.

One of the chemical messengers the pituitary gland sends out to your body is called growth hormone, which is essential for growth.

When the pituitary gland doesn’t make enough growth hormone and sometimes other pituitary hormones as well, the condition is called hypopituitarism. This can slow down a kid’s growth.

Special tests can find out if kids don’t produce enough growth hormone. If they don’t, daily shots of growth hormone can often help them grow to be normal-sized adults.

Another gland that produces hormones important for growth is your thyroid. You may be able to feel it if you press gently with your fingers across the front of your neck, just under your Adam’s apple (elevated throat region of males).

It is shaped like a butterfly and moves up and down when you swallow.

Your thyroid makes a hormone called thyroxin. If it makes too little, the condition is called hypothyroidism.

Having too little thyroxin makes a kid grow more slowly. Doctors can do a simple blood test for hypothyroidism. If it’s needed, a kid can take the missing hormone as a pill.

Other reasons why kids might not grow normally:

Hormones play a major role in growth, but kids might not grow normally for other reasons, including:

1. Chronic diseases:

These include heart and kidney problems, cystic fibrosis, juvenile rheumatoid arthritis, and sickle cell anemia, which may slow growth in some cases.

2. Complications during pregnancy:

One of the reasons a pregnant woman is warned not to smoke or drink is because it may slow down her baby’s growth. A baby may be too small when it’s born and some remain small for life.

Some infections during pregnancy, other pregnancy problems, and certain. genetic diseases can also cause this problem.

3. Failure to thrive :

Some babies do not grow and gain weight normally after they are born. This is called failure to thrive (FTT). FTT may happen when a child simply doesn’t get enough to eat.

Some babies may have an illness that needs to be treated, but most will grow normally after they start

4. Genetic conditions:

Some genetics eating enough food. conditions can also cause children to not grow as they should.

Many of these growth disorders can be successfully treated today. With help, kids who might once have ended up very short can grow up more like other children.

Body Mass Index (BMI):

The body mass index (BMI) or Quetelet index is a value derived from the mass (weight) and height of an individual.

The BMI is defined as the body mass divided by the square of the body height and is universally expressed in units of kg/m2, resulting from mass in kilograms and height in meters.

The BMI is an attempt to quantify the amount of tissue mass (muscle, fat, and bone) in an individual, and then categorize that person as underweight, normal weight, overweight, or obese based on that value.

However, there is some debate about where on the BMI scale the dividing lines between categories should be placed.

The body mass index (BMI) is a statistic developed by Adolphe Quetelet in the 1900s for evaluating body mass.

It is not related to gender and age. It used the same formula for men as for women and children.

The body mass index is calculated based on the following formula:

BMI=\(\frac{Weight in Kilograms}{height in Metre2}\)

Example for 175 cm height and 70 kg weight: BMI-70/(1.75 x 1.75) = 22.86

The result is in kilograms by meter square, or kg/m2. BMI is a crude method to estimate obesity. Body Mass Index (BMI) is one of the ways to determine when extra fat accumulates.

translates into health risks. Body mass index is a measure that takes into account a person’s weight and height to gauge total body fat in adults.

The higher the body mass index, the greater the risk of developing additional health problems. The following chart describes the various categories of obesity based on body mass index

 

 

BMI < 15 (Excessively low weight)

BMI 16-18 (Low weight)

BMI 19-24.9 (Desirable)

BMI 25-29.9 (Overweight)

BMI30-34.9 (Obese, category 1)

BMI 35-39.9 (Obese, category 2)

BMI > 40 (Severe obesity)

Heart disease, diabetes, and high blood pressure are all linked to being overweight and obese.

Interesting Facts About Human Body

The human body is made up of a head, a neck, a torso (trunk), two arms, and two legs. The average height of an adult human is about 5 to 6 feet.

The human body is made to stand erect, walk on two feet, use the arms to carry and lift, and have opposable thumbs (able to grasp).

The adult body is made up of 100 trillion cells, 206 bones, 650 muscles, and 22 internal organs.

Every square inch of the human body has about 19 million skin cells.

In every hour about 1 billion cells in the human body must be replaced.

The average human head has about 100,000 hairs.

The average adult takes over 20,000 breaths a day.

The circulatory system of arteries, veins, and capillaries is about 60,000 miles long.

The heart beats more than 2.5 billion times in an average lifetime.

There are about 9,000 taste buds on the surface of the tongue, in the throat, and on the roof of the mouth.

The strongest (powerful) muscle in the body is the tongue.

The human heart creates enough pressure when it pumps out to the body to squirt blood bo 30 feet.

You blink over 10,000,000 times a year.

The human brain weighs about 3 pounds.

The brain uses over a quarter of the oxygen used by the human body.

Your heart beats around 100000 times a day, 36500000 times a year, and over a billion times if you live beyond 30.

Red blood cells carry oxygen around the body. They are created inside the bone marrow of your bones.

The color of human skin is determined by the level of pigment melanin that the body produces. Those with a small amount of melanin have light skin while those with a large amount have dark skin.

Adult lungs have a surface area of around 70 square meters.

Humans have a stage of sleep that features rapid eye movement (REM). REM sleep makes up around 25% of total sleep time and is often when you have your most vivid dreams.

Most adults have 32 teeth.

The smallest bone found in the human body is located in the middle ear. The stapes (or stirrup) bone is only 2.8 millimeters long.

Infants blink only once or twice a minute while adults average around 10.

As well as having unique fingerprints, humans also have unique tongue prints.

The left side of your body is controlled by the right side of your brain while the right side of your body is controlled by the left side of your brain.

Antibiotics are only effective against bacteria; they do not help in fighting off a virus.

It takes about 12 hours to completely digest eaten food.

Your sense of smell is around 10000 times more sensitive than your sense of taste.

It takes about 20 seconds for a red blood cell to circle the whole body.

One-fourth of the bones in your body are in your feet.

The blood processing in the kidneys amounts to some 1.25 liters a minute, or 1800 liters a day (1.25 × 60 × 24 = 1800), which is about 400 times the total blood volume and roughly one-fourth the volume pumped each day by the heart.

Every 24 hours, 170 liters of water is filtered from the bloodstream into the renal tubules; and by far the greater part of this- some 168.5 liters of water together with salts dissolved in it is reabsorbed by the cells lining the tubules and returned to the blood.

In a 24-hour period, an average man eliminates only 1.5 liters of water, containing the waste products of metabolism, but the actual volume varies with fluid intake and occupational and environmental factors.