WBBSE Solutions For Class 7 Geography Chapter 4 Landforms Topic C Plains

Chapter 4 Landforms Topic C Plains Analytical Type Questions

Question 1. Classify plains with examples.
Answer:

Classification of plains:

A ‘plain’ refers to an area of land that is not significantly higher than the adjacent areas and has relatively minor differences in elevation, generally less than 300 metres, within the area. Plains can be of different types.

These are discussed below-

1. Alluvial plain:

Alluvial plains are formed by the deposition of silt, brought down by the rivers.

WBBSE Solutions For Class 7 Geography

Example: Indo-Gangetic Plain.

 

2. Loess plain:

Loess plains are formed due to the continuous accumulation of fine-grained sand particles blown away by winds from deserts and deposited in far-off places.

Example: Loess plains have formed in the Hwang Ho river basin due to the deposition of sand particles blown away by the wind from the Gobi desert.

3. Lava plain:

These plains are formed by the accumulation of lava that seeps out from the fissures and deposits over vast, flat, low-lying stretches.

Example: Lava plain of Iceland.

All the above-mentioned plains fall under the category of depositional plains. The plains that develop from the depositions brought down by the agents of erosion, such as rivers, wind, sea waves or glaciers are called depositional plains.

Glacial plains and Bajada also are depositional plains. Apart from depositional plains, there can be two more types of plains namely, erosional plains and tectonic plains.

Erosional plains can be further divided into peneplain and pediplain whereas tectonic plains are classified into uplifted plains and subsided plains.

Question 2. Explain the influence of plains on human life.
Answer:

Influence of plains on human life:

Plains have a great influence on human life. Some of the important ones are discussed below-

1. Development of agriculture:

The soil of most plains are generally formed by the deposition of silt, which makes plains fertile. Thus, agricultural activities are quite developed in the plains.

2. Development of transport and communication:

Development of railways, roadways and waterways is easier on the plains. It helps in better transport and communication.

3. Industrialisation:

The establishment of industries in the plain regions is always easier than in regions with rough terrain. Due to extensive agricultural activities and improved transportation and communication system, many agro-based and labour-intensive industries have developed in the plains.

4. Water for drinking and irrigation purposes:

Major parts of most rivers flow through the plains making water easily available for drinking and irrigation purposes.

5. Suitable environment for living:

Plains are the most favourable places to live among all types of landforms.

6. Urbanisation:

The fact that life is easier in the plains has given rise to the world’s biggest urban areas in the plain regions.

7. Development of animal-rearing farms:

In plain regions, the lands which are not used for agricultural activities, are used as grazing fields for farm animals.

8. Development of pisciculture:

Due to the presence of rivers, waterbodies and sometimes proximity to the sea, the plains are quite suitable for pisciculture and fishing.

Question 3. How do landforms influence our lives?
Answer:

Impact of landforms on human life:

Landforms are intimately related to the ways of our lives. Human lifestyle adjusts itself to the local landforms in all parts of the world. Landforms control our livelihood patterns, social and cultural activities, economic activities etc.

Landforms affect our lives in the following ways-

Impact of mountains:

Suitable for agriculture and animal rearing:

The slopes of mountains are ideal for animal rearing as these are extremely suitable for grazing. Mountains also directly influence step farming or terrace farming.

1. Favourable for tourism:

Mountains are very popular tourist spots. Some popular hill stations are Ooty, Shimla, Darjeeling etc. The elevation, climate and natural beauty of mountains always attract tourists which directly influences the livelihood of the locals.

2. Development of industries:

Rivers originating from the mountains are quite swift and this property is utilised for the development of hydroelectric power plants in the mountainous regions. This, in turn, has contributed significantly in the development of industries.

Impact of plateaus:

1. Source of minerals:

Plateaus are mainly made up of igneous rocks and thus are rich in minerals. So the plateau religious acts as an important natural source of industrial raw materials, that has led to the development of many mineral-based industries.

2. Suitable for animal husbandry:

Plateau regions have rugged and stony terrain that is not favourable for cultivation. However, the extensive grasslands of these regions help in grazing and thereby promote animal husbandry.

3. Impact of plains:

1. Suitable for agriculture:

Most of the plains have formed due to the deposition of silt that makes them very fertile. Due to this fertile soil, agricultural activities are extensively carried out in the plains.

Easy livelihood:

Plains are the most suitable place for agriculture, industrial activities, transport and communication etc. All these facilities bring different opportunities, which make lives easier.

The suitable living place for humans:

Due to low elevation, easy availability of drinking water and food, favourable agricultural and industrial practices, easy transport system, etc, plains are the most convenient of all landforms to live.

Question 4. What are the differences between mountains, plateaus and plains?
Answer:

Differences between mountains, plateaus and plains:

The differences between mountains, plateaus and plains are discussed in the following table-

Chapter 4 Landforms Topic C Plains Short Analytical Type Questions

Question 1. Give a brief account on the origin of plains.
Answer:

Origin of plains:

The origin of plains can be attributed to any one of the following causes-

1. Erosion:

Prolonged erosion of highlands leads to the formation of plains.

2. Deposition:

Prolonged sedimentation and filling of lowlands result in a plain. This may occur due to the action of natural agents like wind, rivers, glaciers, etc.

3. Tectonic movement:

The accumulation and solidification of lava over time also lead to the formation of a certain type of plain known as a lava plain.

Question 2. What are the characteristics of a plain?
Answer:

The different characteristics of a plain are as follows-

1. Slope:

The plains usually have a very gentle slope meeting the sea surface.

2. Height:

The height of a plain is generally less than 300 metres from the sea level.

3. Type of soil:

As the plains are generally made up of alluvial soil, they are fertile and important for agriculture.

4. Location and expanse:

Among the three types of landforms, plains occupy the largest part on the Earth’s surface. Most of the plains in the world have formed along river valleys and sea coasts.

Question 3. Write any three differences between a mountain and a plateau.
Answer:

Question 4. Write any three differences between a plateau and a plain.
Answer:

Question 5. Why does the majority of the world’s population live on the plains?
Answer:

The majority of the world’s population lives on the plains, because-

1. Most plains are made up of fertile alluvium, and so agriculture is highly developed in this region.
2. The flat of a proper transport system comprising railways, roadways and waterways.
3. As the region is developed in agriculture and communication system, different types of industries, like agro-based industries can easily develop and grow.
4. Most of the large rivers flow over plains and so there is no scarcity of water for drinking or irrigation.

Chapter 4 Landforms Topic C Plains Short Answer Type Questions

Question 1. What is a plain?
Answer:

Plain:

An extensive region of land area with an elevation that is slightly higher than sea level. and a very gentle slope is called a plain. The average height of a plain is generally less than 300 metres.

Example: The Indo-Gangetic Plain of North India. Extensive regions of Punjab, Uttar Pradesh, Bihar and West Bengal are a part of this plain.

Question 2. What is an alluvial plain?
Answer:

Alluvial Plain:

Generally alluvium and sand carried by a river get deposited on both sides of the river or at its mouth forming a flat fertile surface or plain, which is called an alluvial plain.

Example: Ganges Plain, Plains of Hwang-Ho etc.

Question 3. What is a loess plain?
Answer:

Loess plain:

Fine sand particles get carried by the wind from deserts to distant low-lying areas. The prolonged deposition of these fine sand particles in the low-lying areas leads to the formation of a plain called loess plain.

Example: The loess plain along the Hwang Ho river basin formed from loess sediments from the Gobi Desert.

Question 4. How is a lava plain formed?
Answer:

Hot and molten magma from the interior of the Earth erupts as lava on the surface of the Earth and solidifies to form a type of plain called lava plain.

Example: The northern part of the Deccan Plateau is a lava plain commonly known as the Deccan Traps.

Question 5. Write two differences between alluvial plain and loess plain.
Answer:

Two differences between alluvial and loess plain are-

Formation: Alluvial plains are formed by the silt brought down by the rivers.

On the other hand, loess plains are formed due to the accumulation of sand particles blown away by winds from deserts and deposited far-off places.

Fertility: Alluvial plains are fertile.

On the other hand, loess plains are infertile.

Chapter 4 Landforms Topic C Plains Multiple Choice Questions Choose The Correct Option

Question 1. Most of the land areas on the Earth are-

1. Plains
2. Plateaus
3. Mountains

Answer: 1. Plains

Question 2. The average altitude of a plain from the sea level is-

1. Less than 300 metres
2. More than 300 metres
3. More than 600 metres

Answer: 1. Less than 300 metres

Question 3. The Northern Plains of India are an example of-

1. Alluvial Plains
2. Coastal Plains
3. Glacial Plains

Answer: 1. Alluvial Plains

Question 4. An example of a lava plain is-

1. Deccan Trap
2. Indo-Gangetic Plain
3. Brahmaputra Plain

Answer: 1. Deccan Trap

Question 5. _______ are formed due to the deposition of sand carried by wind to distant places.

1. Alluvial plains
2. Loess plains
3. Coastal plains

Answer: 2. Loess plains

Question 6. Which of the following is formed by the deposition of sand particles?

1. Alluvial plain
2. Loess plain
3. Lava plain

Answer: 2. Loess plain

Question 7. The world’s largest deltaic plain has been formed at the mouth of the river-

1. Ganges
2. Nile
3. Tigris

Answer: 1. Ganges

Question 8. Maximum population density is observed in the-

1. Plains
2. Plateaus
3. Mountains

Answer: 1. Plains

Question 9. Sustenance of life is much easier in the-

1. Plains
2. Mountains
3. Plateaus

Answer: 1. plains

Question 10. Most ancient civilisations have thrived on-

1. Alluvial Plains
2. Lava Plains
3. Loess Plains

Answer: 1. Alluvial Plains

 

Chapter 4 Landforms Topic C Plains Very Short Answer Type Questions

Question 1. Generally, river-based civilisations have flourished in the __________ regions.
Answer: Plain

Question 2. The Indo-Ganga-Brahmaputra plain is an __________ plain.
Answer: Alluvial

Question 3. Loess plains are found in the __________ river basin.
Answer: Hwang Ho

Question 4. The plainland of Pampas is in __________.
Answer: South America

Question 5. The Nile River Basin is an example of a __________ plain.
Answer: Flood

Question 6. The most famous plain of South America is __________.
Answer: Pampas

Question 7. A __________ is the most fertile region among all landforms.
Answer: Plain

Question 8. A notable plain of North America is __________.
Answer: Prairie

Chapter 4 Landforms Topic C Plains Write True Or False

Question 1. The Ganga Plain is an example of an alluvial plain.
Answer: True

Question 2. A loess plain is formed due to the deposition of lava.
Answer: False

Question 3. The upper surface of a plain is undulating.
Answer: False

Question 4. Both internal and external forces are responsible for the formation of plains.
Answer: True

Question 5. The highest density of population is found in the plains.
Answer: True

Question 6. Flood plains are examples of the depositional plains.
Answer: True

Question 7. Alluvial plains are formed due to the deposition of alluvium.
Answer: True

Question 8. Plains do not have any influence on human life.
Answer: False

Question 9. Glacial plains and Bajada are examples of the erosional plains.
Answer: False

Question 10. The slope of a mountain is ideal for animal rearing.
Answer: True

Chapter 4 Landforms Topic C Plains Match The Columns

1.

Answer: 1. D, 2. C, 3. A, 4. B

Chapter 4 Landforms Topic C Plains Answer In One Or Two Words

Question 1. Which is the world’s largest deltaic plain?
Answer: Ganga-Brahmaputra Plain.

Question 2. What is formed by the deposition of alluvial sediments that are brought down by rivers over a period of time?
Answer: Alluvial plain.

Question 3. What do we call A-shaped flat plains formed by alluvium deposition on river beds?
Answer: Deltaic plain.

Question 4. What do we call a large expanse of nearly flat plains formed by the accumulation of lava?
Answer: Lava plain.

Question 5. Which type of plain can be seen in Iceland?
Answer: Lava plain.

Question 6. What kind of landform is created by the deposition of sand or silt particles carried by the wind from one place to another?
Answer: Loess plain.

Question 7. Where can we find the plain land of Prairies?
Answer: North America.

Question 8. Which type of landform enables an easy livelihood?
Answer: Plains.

Chapter 4 Landforms Topic C Plains Miscellaneous Type Questions Find The Odd One Out

Question 1. Hill: River: Plateau: Plain
Answer: River (not a landform)

Question 2. River: Wind: Glacier: Asthenosphere
Answer: Asthenosphere (not an exogenic force)

Question 3. Aravalli: Himalaya: Alps: Andes
Answer: Aravalli (not a fold mountain)

Question 4. Vesuvius: Fujiyama: Himalaya: Krakatoa
Answer: Himalaya (not a volcanic mountain)

Question 5. Deccan Plateau: Tibetan Plateau: Malwa Plateau: Columbia Plateau
Answer: Tibetan Plateau (not a volcanic plateau)

Question 6. Tibetan Plateau: Deccan Plateau: Pamir Plateau: Bolivian Plateau
Answer: Deccan Plateau (not an intermontane plateau)

Question 7. Darjeeling: Puri: Ooty: Shimla
Answer: Deccan Plateau (not an intermontane plateau)

Chapter 4 Landforms Topic C Plains Correct The Following

Question 1. The arrangement of landscape on the surface of the Earth is known as hill.
Answer: Landform

Question 2. The continental and oceanic plates float on the ocean.
Answer: Asthenosphere

Question 3. Aravalli is a new fold mountain.
Answer: Himalaya

Question 4. Satpura is a volcanic mountain.
Answer: Block

Question 5. stretch of the geographic area consisting of mountain peaks and valleys is known as a knot.
Answer: Mountain range

Question 6. Ladakh Plateau is called the ‘Roof of the World’.
Answer: Pamir Plateau

Question 7. The aeolian (wind-blown) sediments from the deserts accumulate to form a deltaic plain.
Answer: Loess

Who Am I?

Question 1. I am a rocky highland. My average height is more than 900 metres above sea level. Who am I?
Answer: Mountain

Question 2. I extend over a wide area, comprising a chain of mountains. Who am I?
Answer: Mountain range

Question 3. I am the topmost portion of a mountain, resembling the shape of a needle. Who am I?
Answer: Mountain peak

Question 4. I am the lowland between two mountains. Who am I?
Answer: Valley

Question 5. I am a special type of mountain formed due to the folding of my rock beds. Who am I?
Answer: Fold mountain

Question 6. I am a chain of young fold mountains located to the north of India. Who am I?
Answer: Himalayas

Question 7. I am a steep-sloped highland resembling the shape of a table. Who am I?
Answer: Plateau

Question 8. I am a tabular landform surrounded by mountains on all sides. Who am I?
Answer: Intermontane Plateau

Question 9. I am the highest plateau in the world. Who am I?
Answer: Pamir Plateau

Question 10. I am a junction of several mountain ranges. Who am I?
Answer: Knot

Question 11. I am a flat plain formed by the deposition of fine sand particles blown by winds. Which type of plain am I?
Answer: Loess plain

Question 12. A number of river valley civilisations have developed on me. Who am I?
Answer: Plain

Scrambled Words

1. DOENNICGE
2. CAVOLNIC
3. VALARALI
4. TNKO
5. JAKIMANROLI
6. TALTICONNEN
7. ELOSS
8. TOTECNIC
9. YAMAHILA
10. SSFOIL

Answers:

1. ENDOGENIC
2. ARAVALLI
3. VOLCANIC
4. KNOT
5. KILIMANJARO
6. CONTINENTAL
7. LOESS
8. TECTONIC
9. HIMALAYA
10. FOSSIL

Chapter 4 Landforms Topic C Plains Fill Up The Blanks In The Knowledge Hive

Question 1. Fill up the knowledge hive with information about the ways in which mountains influence our lives.

Answers:

1. The crust is divided into small parts. These parts are known as plates, which are floating on the Asthenosphere.
2. These plates are moving because of the convectional current that is going on in the Asthenosphere.
3. When two plates move towards each other, the oceanic plate will move below the continental plate as it is heavier.
4. As the thickest deposits of sedimentary rocks are accumulated at the edges of the continent, they crumple due to the convergent movement of the plates and fold mountains are formed.

Question 2. Fill up the knowledge hive with the information about the process of fold mountain formation.

Answers:

1. Generate several perennial rivers.
2. Mountains act as barriers for wind flow and produce orographic rainfall.
3. Mountains influence the climate of a country or a region.
4. Rivers originating from the mountains generate hydroelectricity.
5. Softwood forests are found here.
6. Make ideal tourist spots.

Crossword

Question 1.

 

Clues

Down:

5. Plains of South America.
6. A fold mountain in North America.
7. A fold mountain in South America.

Across:

1. A fold mountain in Europe.
2. A volcanic mountain in Japan.
3. A block mountain in India.
4. A fold mountain in Asia.

Answers:

Down: 5. PAMPAS, 6. ROCKY, 7. ANDES
Across: 1. ALPS, 2. FUJIYAMA, 3. SATPURA, 4. HIMALAYAS

Question 2.

Clues

Down:

2. Fold Mountain in North America.
3. Block Mountain in India.
4. Intermontane plateau between the Himalayas and Kunlun.
5. Darjeeling is a famous spot.

Across:

1. Landforms exceeding 1000m in height.
6. A famous hill station in South India.
7. A volcano in Sicily.

Answers:

Down: 2. ROCKY, 3. SATPURA, 4. TIBET, 5. TOURIST
Across: 1. MOUNTAIN, 6. OOTY, 7. ETNA

Chapter 4 Landforms Topic C Plains Advanced Questions And Answers

Question 1. What are active volcanoes?
Answer:

Active volcanoes:

The volcanoes which erupt often are called active volcanos. These volcanoes are of two types-

1. Volcanoes which erupt incessantly example Mt. Vesuvius in Italy.
2. Volcanoes which erupt intermittently example Stromboli in Italy.

Question 2. What are dormant volcanoes?
Answer:

Dormant Volcanoes:

The volcanoes which have not erupted for a long time but can erupt at any moment, are called dormant volcanoes.

Example: Mauna Kea in Hawaii, Mt. Kilimanjaro in Africa.

Question 3. What is an extinct volcano?
Answer:

Extinct Volcano:

The volcanoes which have erupted in historical times, but do not show any sign of eruption in the future are called extinct volcanoes.

Example: Mount Popa in Myanmar.

Question 4. Name the mountain ranges radiating from the Armenian Knot.
Answer:

Several mountain ranges radiate in different directions from the Armenian Knot. They are-

Question 5. Name the mountain ranges radiating from Pamir Knot.
Answer:

Several mountain ranges radiate in different directions from the Pamir Knot. These are-

Question 6. What is a geosyncline?
Answer:

Geosyncline:

Shallow seas in the interior of any continent or at the edge of any continent where deposition of sediments takes place accompanied by folding and crumpling of the deposits, gets transformed into a belt of folded mountains, called geosynclines.

Characteristics:

The characteristics of geosyncline are-

1. They are narrow, elongated and shallow water bodies.
2. The geosynclines become shallow and subside due to the accumulation of the vast amounts of sediments.
3. Geosynclines are surrounded by continental landmasses called foreland.

Example:

Tethys Geosyncline between Angaraland and Gondwanaland.

Question 7. Write the differences between epeirogenic and orogenic movements.
Answer:

The differences between epeirogenic and orogenic movements are-

Question 8. Write a short note on the anticline and syncline.
Answer:

Anticline and Syncline:

Fold mountains consist of different types of folds. The apex of the fold pointing upwards is called an anticline and the apex of the fold pointing downwards is called a syncline.

In other words, the crest between any two bends is called an anticline (A-shaped) and the trough is called a syncline (V-shaped).

Question 9. Write a short note on fossils.
Answer:

Fossils:

Fossils are the preserved remains or traces of animals, plants or other organisms from the ancient past buried inside the sedimentary rocks millions of years ago.

Example: Glossopteris.

Importance of fossils: With the help of fossils-

1. The age of the rocks can be estimated,
2. The climate during the historic times can be assumed,
3. The nature of the organisms which lived in the historic times can be understood.

Question 10. What is a crater?
Answer:

Crater:

The mouth or opening at the top of a volcanic mountain through which magma, gas, ash, etc. erupt, is called a crater. The crater is connected to the magma chamber inside the Earth through a cylindrical path called a vent.

The diameter of a crater may vary from a few metres to a few kilometres. Some volcanoes have subsidiary cones beside the main crater.

Sometimes lake can also be formed in a crater which is called a crater lake. Lake Pinatubo of the Philippines is an example of a crater lake located at the mouth of a volcanic crater.

Question 11. What is a caldera?
Answer:

Caldera:

The mouth of a volcano through which lava, gas, ash, etc. are ejected is called a crater. A large but shallow crater is called a caldera. Calderas are usually formed when the existing volcanic cone gets blown off.

Sometimes calderas are formed due to the collapse of craters. The word caldera has been derived from the Latin word ‘caldaria’ meaning ‘cooking pot’.

Chapter 4 Landforms Topic C Plains Formative

Interpretation And Application

This segment will test whether the students have understood the topics, or whether they are just memorising them.

Question 1. Solve it if you grasp it.

Answer:

Question And Experimentation

This segment will investigate the student’s understanding of the subject, questioning capacity, ability to explain and apply and urge for experimentation

Question 1. By showing the pictures, the teacher checks the students’ enthusiasm and interest in asking questions. Does the teacher want to know what are these pictures.

Answer:

Student: The first one is a picture of a mountain, the second one is a picture of a plateau and the third one is of a plain. Okay! are they all created at once?
Teacher: Not at all. They have been created for different reasons, at different times, in different ways.
Student: How did such a high mountain come to be?
Teacher: The picture is of a fold mountain. The terrain on which we stand is not static, it is moving. This Earth’s crust is made up of large and small plates which are floating on a viscous layer (Asthenosphere). When two plates are facing each other, the sediments of the shallow sea in the space between fold to form such a mountain.
Student: Are all mountains formed in the same way?
Teacher: Not at all. Many times hot underground magma comes out and solidifies in the form of lava to form volcanic mountains. Sometimes tectonic movements occur and the surface of the Earth ruptures and rises to form block mountains. Sometimes, due to the action of rivers, glaciers, winds, weathering, etc. those mountains get eroded and form residual mountains or hills.
Student: Are plateaus, and plains also formed in different ways?
Teacher: Yes, they are all created by different ways. That can be explained later.

Interpretation And Application

This segment will test whether the students have understood the topics, or whether they are just mugging up.

Question 1. Write the method of making shapes of different landforms with the help of a square paper.
Answer:

Mountain making:

Fold a square of paper into a triangle or into three corners. Look at the top of the paper that becomes sharp like a needle. This part can be considered as a mountain peak.

Because it is the highest part of that triangular piece of paper. Overall, the triangular paper may be considered as a replica of a mountain.

Plateau making:

Now the sharp part of the top of the triangular paper is folded a little. Then the sharp, pointed part of the paper is flattered and lowered. This shape of this paper resembles like a plateau.

Plain making:

Fold the top of the paper one more time and the top side becomes more flat and lower. With such a shape, the idea of the shape of a plain can be found.

Question 2. Explain how a fold mountain is formed with the help of a mat.
Answer:

Fold mountain is formed with the help of a mat:

We ourselves can explain how a fold mountain is formed with the help of a mat. At first, a mat is stretched on a plain floor. Now push the mat from two sides or ends towards the middle. Then the mat gradually folds and rises upwards.

Thus, when the plates come forward and collide against each other, the accumulated sediments fold in the middle under strong pressure from the two moving plates and rise to form a fold mountain.