WBBSE Solutions For Class 10 Life Science And Environment Chapter 2 Growth And Development

Chapter 2 Growth And Development Summary

WBBSE Class 10 Growth and Development Overview

• Growth is an important and distinct characteristic of life. Growth is an anabolic process through which the size, volume and dry weight of organisms is increased. Development is the increasing complexity in organisms.
• There are three phases of growth, viz-

1. A phase of cell division,
2. A phase of cell enlargement and
3. A phase of cell differentiation.

• In the phase of cell division, the number of cells increases. The volume of protoplasm increases during the phase of cell enlargement, whereas, cells metamorphose into the tissue, organ through a phase of cell differentiation.
• The physical, mental and emotional changes those are evident with the course of time is called development in human. In human life, there are five phases of development, viz.-

1. Newborn,
2. Childhood,
3. Adolescence,
4. Matured phase and
5. Old age or late mature phase.

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Chapter 2 Growth And Development Long Answer Type Questions

Question 1. What is growth? Explain different types of growth in living organisms.

Answer:

Growth:

Growth is an anabolic process by which the size and dry weight of any living organism increases permanently and irreversibly, by means of cell division.

Types of growth in living organisms:

In living organisms, three different types of growth can be noticed. These are-

1. Vegetative growth:

By this process, a unicellular zygote divides consecutively to give rise to a fully formed multicellular organism. For example, the events of germination of seeds, growth of saplings, and formation a full-grown plant are treated as vegetative growth.

2. Regenerative growth:

The damaged and injured parts of any living body are repaired or healed by this process of growth.

3. Reproductive growth:

This process of growth helps any organism to become reproductively capable. By this growth process, the reproductive organs of young organisms attain maturity and start producing gametes. In plants, this growth process is seen in flowers, fruits and seeds.

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Question 2. Name three main phases of growth. Briefly describe those phases.

Answer:

Phases of growth:

The growth of multicellular organisms can be divided into three phases.

These are-

1. The phase of cell division,
2. The phase of cell enlargement and
3. The phase of cell differentiation.

Description of the phases of growth:

Wbbse Class 10 Life Science

The three different phases of growth are described below.

1. Phase of cell division:

In this phase, cells divide mitotically to increase in number in a living body. Cells of apical and lateral meristem divide to make a plant body grow in length and width.

In animals, a unicellular zygote divides repeatedly and undergoes through different stages, like morula, blastula, and gastrula of a multicellular embryo to give rise to a fully grown animal body.

2. Phase of cell enlargement:

In this phase, the newly divided cells absorb water and synthesise different cellular components to increase the protoplasmic volume. By this process, the cells become larger and the tissues formed by these cells grow in volume irreversibly.

In some tissues, secretory materials accumulate in the intercellular spaces to increase the volume of that region, as we can see in bones and cartilage.

 

3. Phase of cell differentiation:

In this phase, the fully grown daughter cells slowly modify and gain certain specialised features. These typical cells then form different tissues and tissue systems to perform specific functions.

Finally, these tissue systems form different organs and organ systems of a living body.

Wbbse Class 10 Life Science

Question 3. Briefly describe the five stages of human development.

Answer:

Phases of human development:

According to WHO human development includes five different stages which are described below.

1. Newborn or neonatal phase:

This phase of development lasts for the first one month after the birth of a baby. During this phase, the baby remains asleep most of the time and shows a very high rate of metabolism.

In this phase, a baby can detect light, the direction of sound, primary colours and above all, can recognise the mother’s face. Body weight may reduce during the first few days but soon it resumes. For newborn babies, laughing and crying are the main signs of communication.

2. Childhood:

This phase of life starts from the second month and continues up to ten years. During this period, physical, mental and emotional development occurs at a faster rate. Motor activities increase and limbs grow quicker than other parts of the body.

Power to memorise, the ability of reading, writing, drawing and problem-solving improve gradually. A child can express fear, anger and excitement but finer emotions are not expressed perfectly.

3. Adolescence:

This is the intermediate phase between childhood and adulthood. The span between the age of 10 to 19 years (according to WHO) is treated as adolescence. The age of adolescence is not fixed for all. It varies with gender, environment, nutrition, geographical location, etc.

During this phase, several hormones come into action to regulate the growth and functioning of sexual organs. An adolescent boy and girl go through significant changes in physical, mental, emotional and social aspects.

From this phase of life, sexual attraction towards the opposite gender emerges. Mature gamete formation starts during this phase. Concentration, thinking skills, analytical ability and intelligence grow very fast in adolescent individuals.

At this age, they dare to take risks. Therefore, adolescence is treated as the ‘period of turmoil.

4. Adulthood or matured stage:

The age between 19 to 60 years is denoted as adult age. This phase is characterised by maturity, self-confidence, practical, purposeful and self-directed attitude. In this period, physical growth reduces quickly and ultimately stops.

At this age, a sense of responsibility towards family and society grows significantly. An adult person gains experiences of life and mostly follows moral values.

Wbbse Class 10 Life Science

5. Old age:

The age beyond 60 years is treated as old age. In this age, cellular activities gradually slow down. Visual and auditory abilities get weakened. Old age is characterised by thinning and greying of hair.

Skin gets heavily wrinkled and muscles become weak. Bones gradually degenerate and joints lose their movability which are the consequences of different bone diseases like osteoporosis and osteoarthritis. People at old age lose memory and become mentally fatigued.

 

 

Question 4. Distinguish between the growth and development processes in human beings.

Answer:

Difference between human growth and development processes

Types of Growth in Living Organisms

Question 5. Mention the changes that occur in adolescent males and females.

Answer:

Changes in adolescent males and females:

Several changes occur in adolescent males and females. These are mentioned below.

In male:

1. The male reproductive organs become fully grown to produce gametes and secrete sex hormones.
2. Development of the endocrine glands present all over the body is completed.
3. Body weight and height increase at a faster rate.
4. Sweat and sebaceous glands get stimulated. Hypersecretion of these glands results in oily facial skin, thereby causing acne.
5. Beards grow on the face, hairs develop on the chest, armpit and pubic region.
6. Muscles and bones become stronger and the voice becomes husky.

 

 

In female:

1. Female reproductive organs become adolescence completely developed and start producing gametes and secreting sex hormones.
2. The beginning of the menstrual cycle is the indication of the onset of puberty.
3. Mammary glands grow in size during this time.
4. Body weight and height increase in females during adolescence.
5. Additional fat below the skin gives lustre to it.
6. Deposition of extra fat in hip and thigh region gives the body a feminine shape.
7. Hyperactivity of sweat and sebaceous glands makes the face oily, due to which acne grows.
8. Hairs grow on armpits and pubic regions.

 

Chapter 2 Growth And Development Short Answer Type Questions

Question 1. What is meant by development?

Answer:

Development:

Development is the collective changes, including growth and other transformations, which occur continuously since the formation of a zygote until the death of any organism. It is a quantitative change in a multicellular organism.

Question 2. ‘Development is impossible without growth’- Explain.

Answer:

‘Development is impossible without growth’:

Growth refers to an increase in the measurable, physical size of the whole or any of definite part of an organism. Whereas, development refers to the quantitative as well as the qualitative changes in the organism as a of whole.

Life of any multicellular organism starts with a unicellular zygote which increases in cell number by cell division and increases complexity at the tissue or organ level by cell differentiation.

The development also can be defined as the increase of complexity. impossible without growth. So we can easily say that ‘development is impossible without growth’.

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Question 3. Write the differences between plant growth and animal growth.

Answer:

The differences between plant growth and animal growth are-

Factors Affecting Growth and Development

Question 4. What is meant by human development?

Answer:

Human development:

Human development is the collective irreversible changes in a physical, mental and emotional state, that any human being encounters from its birth until death.

By this developmental process, a human baby grows into an adult and finally reaches the old age.

Question 5. What is meant by human growth?

Answer:

Human growth:

Human growth is the spontaneous and irreversible change in size, volume, height and weight of a human body with age. By this process, a newborn baby transforms into a fully grown human being.

Question 6. What is meant by positive growth?

Answer:

Positive growth:

When anabolic activities increase in comparison to catabolic activities, the dry weight of the body increases. This change is known as positive growth.

Example: Positive growth is noticed during a grand period of growth in all living beings.

Question 7. What is meant by negative growth?

Answer:

Negative growth:

When catabolic activities increase in comparison to anabolic activities, the dry weight of the body reduces. This change is known as negative growth.

Example: Negative growth is seen during the initiation of seed germination and during senescence.

Wbbse Class 10 Life Science Solutions

Wbbse Class 10 Life Science Solutions

Question 8. Mention different types of growth depending on nature.

Answer:

Depending on nature, growth is of three types.

These are-

1. Vegetative
2. Regenerative growth and
3. Reproductive growth.

Question 9. What is meant by the phase of cell division of ant by the phase of cell division of growth?

Answer:

The phase of cell division of ant by the phase of cell division of growth:

The phase of growth, in which an organism grows physically only by means of mitotic cell division, is known as the phase of cell division of growth.

Example: Growth of an embryo from the zygote, growth of shoot and root apices in plants, etc.

Stages of Plant Growth Explained

Question 10. What is meant by the phase of cell enlargement of growth?

Answer:

The phase of cell enlargement of growth:

The phase of growth, in which the newly divided cells absorb water, and synthesise various proteins, nucleic acids and other organic matters to increase the protoplasmic volume, is known as the phase of cell enlargement of growth. By this process, the overall size of a cell increases.

Question 11. What is meant by the phase of cell differentiation growth?

Answer:

The phase of cell differentiation growth:

After the phase of cell division and cell enlargement, cells undergo structural and functional transformations. In this process, cells develop specialised features and take part in the formation of different tissues and organs. This phase of growth phase of is called of growth cell differentiation.

Question 12. What is meant by continuous growth?

Answer:

Continuous growth:

The type of growth, in which the growing process starts since birth and continues until the attainment of ultimate size and maturity, is treated as continuous growth.

Example-All higher animals including humans – show continuous growth.

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Question 13. What is meant by discontinuous growth?

Answer:

Discontinuous growth:

In certain organisms, the growing process stops intermittently, after every quick period of growth. This type of growth is known as discontinuous growth.

Example: In insects and other arthropods, growth stops before moulting and it starts again after completion of it.

Question 14. How does the vegetative growth of plants occur?

Answer:

Vegetative growth of plants occurs by cell division of primary and secondary meristems. By this process, leaves, branches and roots of plants grow significantly.

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Question 15. What is meant by prenatal phase?

Answer:

Prenatal phase:

The phase of life, starting after the formation of the zygote and ending with the birth of a baby, is known as the prenatal phase. In humans, the span of the prenatal phase is 280 days.

Question 16. What is meant by the neonatal phase?

Answer:

Neonatal phase:

The span of life, starting from the birth of a baby till the completion of one month, is known as the neonatal phase. During this phase, a human baby remains completely dependent upon others.

Question 17. Write down the characteristics of neonates.

Answer:

A few mention-worthy characteristics of neonates are

1. The child can recognise faces, some sounds, and lights.
2. They express themselves only by crying.
3. Their weight increase rapidly.

Question 18. What is meant by childhood?

Answer:

Childhood:

The phase of life, starting from the beginning of the second month until the end of ten years, is known as childhood. During this period, physical, mental and emotional development occurs at a faster rate along with various motor activities.

Question 19. What is meant by adolescence?

Answer:

Adolescence:

The phase of human life, in which secondary sexual characters appear in males and females and the respective reproductive organs start producing gametes and secrete sex hormones, is known as adolescence. This span usually ranges between 10-19 years of age.

Question 20. What are the secondary sexual characters?

Answer:

The secondary sexual characters:

Secondary sexual characteristics are the features that appear during puberty in human beings. These visibe features include maturation of gonads, the emergence of public hair in both males and females, enlarged breasts, the onset of menstruation and widened hips in females and cracked voices, growth of facial hair as well as protrusion of Adam’s apple in males.

Human Growth Stages

Question 21. Write down some characteristics and features of the adolescent phase.

Answer:

Some characteristic features of the adolescent phase are as follows-

1. The rapid growth of the body takes place.
2. Secondary sexual characters develop on the body.
3. Attraction towards the opposite sex develops.
4. The rapid growth of thinking, analytical power and memory takes place.

Question 22. What do you mean by matured phase in human development?

Answer:

Matured phase in human development:

In the case of human development, the phase or period of life from the age of 19 to 60 years is treated as a matured phase. During this phase, physical growth declines and finally stops. Mental maturity, responsibility and decision-making ability reach their peak.

Wbbse Class 10 Life Science Solutions Chapter 2 Question 23.

Question 23. Mention the internal factors responsible for mental and physical changes in an adolescent boy.

Answer:

The internal factors responsible for mental and physical changes in an adolescent boy

In an adolescent boy, different hormones play an important role in changing the mental and physical state. These hormones include GnRH- from the hypothalamus, ICSH from the pituitary and testosterone from the testis.

Question 24. Mention the internal factors responsible for mental and physical changes in an adolescent girl.

Answer:

In an adolescent girl, different hormones play an important role in changing her mental and physical state. These hormones include GnRH from the hypothalamus, FSH and LH from the pituitary and oestrogen and progesterone from the ovary.

Question 25. Mention the signs of old age in a human being.

Answer:

As a person reaches the old age, several signs of old age or senescence appear.

These are as follows

1. Bone and joints become weak.
2. The power of vision and hearing weakens.
3. Loss of memory, fatigue and lack of confidence are manifested.
4. Hairs become thin and grey.

Question 26. What is meant by senescence?

Answer:

Senescence:

Beyond the age of 60 years, certain decelerating changes start to occur in the human body, which continues until death. In the course of time, these gradual changes make a person older. This process of ageing is known as senescence.

Question 27. Mention two changes related to vision and bones at late adulthood or the senescence phase of human development.

Answer:

During adulthood or the senescence phase of human development, some noticeable changes are-

1. Vision: Due to the weakening of eyesight, symptoms of presbyopia can be seen.
2. Bones: Due to the decaying of bones and joints, symptoms of osteoarthritis and osteoporosis can be noticed.

Question 28. What are the measures should be obeyed by people of old age to stay healthy?

Answer:

The measures should be obeyed by people of old age to stay healthy:

To stay healthy people at old age must follow some rules, like

1. Eating adequate but healthy food as the metabolism rate decreases during this age.
2. Easy but regular exercising to stay physically active.
3. Starting a routine to enhance mobility, flexibility balance, to improve sleep and to boost mood and self-confidence.
4. Remaining socially connected with friends and families to maintain physical and mental health.

 

Chapter 2 Growth And Development Very Short Answer Type Questions Multiple Choice Questions And Answers [Mcq]

Question 1. The phase of growth from start to end, when the process of growth occurs at a fast pace, is called—

1. Grand period
2. Lag period
3. Steady period
4. Stagnant period

Answer: 1. Grand period

Question 2. The branch of biological science that deals with the study of senescence and ageing is called—

1. Anthropology
2. Psychology
3. Physiology
4. Gerontology

Answer: 4. Gerontology

Question 3. A permanent increase of dry weight is called—

1. Development
2. Differentiation
3. Division
4. Growth

Answer: 4. Growth

Question 4. The number of phases of growth of organisms is—

1. Four
2. Five
3. Three
4. Two

Answer: 3. Three

Wbbse Class 10 Life Science Solutions Chapter 2

Question 5. The growth of a plant is measured with—

1. Potometer
2. Arc indicator
3. Barometer
4. All of these

Answer: 2. Arc indicator

Question 6. Which of the following is an example of an external factor of growth?

1. Gene
2. Sunlight
3. Hormone
4. All of these

Answer: 3. Hormone

Question 7. Which of the following occurs first during the growth of a developing organism?

1. Cell maturation
2. Cell transformation
3. Cell development
4. Cell division

Answer: 4. Cell division

Question 8. The growth in width of a plant is treated as—

1. Vegetative growth
2. Primary growth
3. Secondary growth
4. Reproductive growth

Answer: 3. Secondary growth

Question 9. The metabolic process that involves the increase in dry weight of the body is denoted as—

1. Anabolic metabolism
2. Catabolic metabolism
3. Differential metabolism
4. All of these

Answer: 1. Anabolic metabolism

Question 10. The metabolic process in which the dry weight of the body decreases is called—

1. Anabolic metabolism
2. Catabolic metabolism
3. Differential metabolism
4. All of these

Answer: 2. Catabolic metabolism

Question 11. In plants, the growth that occurs due to cell division of secondary meristem is called—

1. Reproductive growth
2. Secondary growth
3. Vegetative growth
4. Primary growth

Answer: 2. Secondary growth

Question 12. If catabolism takes over anabolism, the dry weight of the body decreases. This is called—

1. Negative growth
2. Regular growth
3. Irregular growth
4. Positive growth

Answer: 1. Negative growth

Question 13. The second phase of growth is—

1. Cell enlargement phase
2. Cell division phase
3. Cell differentiation phase
4. Late phase

Answer: 1. Cell enlargement phase

Wbbse Class 10 Life Science Solutions Chapter 2

Question 14. The last phase of growth is—

1. The phase of cell enlargement
2. The phase of cell division
3. The phase of cell differentiation
4. Late phase

Answer: 3. Phase of cell differentiation

Question 15. The phrase, in which the origin of different types of blood cells occurs from stem cells, is treated as—

1. The phase of cell division
2. The phase of cell enlargement
3. The phase of cell differentiation
4. The phase of cell ageing

Answer: 3. Phase of cell differentiation

Question 16. Increase in the number of cells in meristem can be treated as—

1. The phase of cell enlargement
2. The phase of cell division
3. The phase of cell differentiation
4. The phase of cell elongation

Answer: 2. Phase of cell division

Question 17. Transformation of meristematic tissue into permanent tissue occurs in—

1. The phase of cell differentiation
2. The phase of cell enlargement
3. The phase of cell division
4. All of these

Answer: 1. Phase of cell differentiation

Question 18. Which phase of human development is associated with the maturity of reproductive organs and reproductive glands?

1. Childhood
2. Adolescence
3. Late adulthood
4. Infancy

Answer: 2. Adolescence

Question 19. The gradual transformation occurring in a plant from germination of seed to the onset of ageing, is called—

1. Senescence
2. Metabolism
3. Growth and development
4. Assimilation

Answer: 3. Growth and development

Question 20. The gradual complexity, that appears in an organism during its life cycle, by means of growth and following changes, is known as

1. Growth
2. Development
3. Division
4. Degeneration

Answer: 2. Development

Question 21. The total number of developmental phases in human life is—

1. Three
2. Four
3. Five
4. Six

Answer: 3. Five

Question 22. If anabolism takes over catabolism, the dry weight of the body increases. This is called

1. Negative growth
2. Regular growth
3. Irregular growth
4. Positive growth

Answer: 4. Positive growth

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Question 23. The organ which is responsible for husky or cracked voice in males is—

1. Chest muscle
2. Larynx
3. Bronchiole
4. Tongue

Answer: 2. Larynx

Question 24. The developmental phase of human life, in which osteoporosis and osteoarthritis appear, I is called the—

1. Childhood
2. Adolescence
3. Matured age
4. Old age

Answer: 4. Old age

Question 25. The developmental phase of human life, in which motor activities grow more, is the—

1. Childhood
2. Neonatal stage
3. Adolescence
4. Matured age

Answer: 1. Childhood

Question 26. The human developmental phase, in which sexual urge starts to develop, is called the—

1. Childhood
2. Matured stage
3. Adolescence
4. Neonatal stage

Answer: 3. Adolescence

Question 27. The ultimate stage of human development is—

1. Development of motor activity
2. The quick development of intelligence
3. Development of abstract idea
4. Degeneration of bone joints

Answer: 4. Degeneration of bone joints

Question 28. Which of the following is not a character of senescence?

1. Wrinkled skin
2. Fatigue
3. Development of bone
4. Degeneration of bones

Answer: 3. Development of bone

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Question 29. The stage of human development, in which the ability for detecting light and sound develops is—

1. Neonatal stage
2. Childhood
3. Adolescence
4. Matured stage

Answer: 1. Neonatal stage

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Question 30. Among vertebrates, indirect development occurs in—

1. Frogs
2. Birds
3. Reptiles
4. Mammals

Answer: 1. Frogs

Question 31. The phase of cell enlargement is controlled by—

1. Thyroxin
2. Somatotropic hormone
3. Insulin
4. ADH

Answer: 2. Somatotropic hormone

Question 32. Development of an organism starts from—

1. Egg cell
2. Male gametes
3. Zygote
4. Ovary

Answer: 3. Zygote

Question 33. The glands which become hyperactive during adolescence are—

1. Sebaceous glands
2. Sweat glands
3. Reproductive glands
4. All of these

Answer: 4. All of these

Question 34. Secondary sexual characters appear during—

1. Childhood
2. Matured age
3. Adolescence
4. Neonatal stage

Answer: 3. Adolescence

Question 35. The quick loss of calcium occurs in the bones of human females—

1. Before puberty
2. Predelivery
3. Postdelivery
4. After puberty

Answer: 3. Postdelivery

Cell Division and Its Role in Growth

Chapter 2 Growth And Development Answer In A Single Word Or Sentence

Question 1. By which life process, the size, shape and dry weight of an organism increase permanently?
Answer: Growth

Question 2. Which type of growth occurs among woody perennial plants?
Answer: Indefinite growth

Question 3. Which type of growth occurs in plants that grow with time, produce flowers and fruits and then die?
Answer: Definite growth

Question 4. Name two plants showing indefinite growth.
Answer: Banyan and mango

Question 5. Name two plants showing definite growth.
Answer: Paddy and wheat

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Question 6. How do you denote the growth of an organism in unit time?
Answer: Growth rate

Question 7. Mention two internal factors of growth regulation.
Answer: Genes and hormones

Question 8. What is produced after the division of a zygote?
Answer: An embryo

Question 9. Which type of cell division leads to the development of an embryo from a fertilised ovum?
Answer: Mitotic cell division

Question 10. In which phase of growth are the tissues formed?
Answer: Phase of cell differentiation

Question 11. What happens to a cell with the synthesis of new organic matter within it?
Answer: With the synthesis of new organic matters within a cell, the size of the cell increases gradually.

Question 12. Why is the growth of plants treated as indefinite growth?
Answer: Since there is no fixed span of growth among plants, the growth of plants is treated as indefinite growth.

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Question 13. Why is the growth of animals treated as definite growth?
Answer: Since the growth of animals continues for a specific period, animal growth is treated as definite growth.

Question 14. Which phase of human growth is treated as a period of turmoil?
Answer: Adolescent period

Question 15. How do you denote the span of human life from the age of two months up to ten years?
Answer: Childhood

Question 16. How do you denote the phase between childhood and adulthood?
Answer: Adolescence

Question 17. At which phase, a maximum level of physical and mental changes occur in human life?
Answer: Adolescence

Question 18. How do you denote the period of human life between the age of 19 to 60 years?
Answer: Adulthood or matured phase

Question 19. How do you denote the growth of an organism, in which all parts of the body grow at an even rate?
Answer: The growth of certain organisms, like fishes, where all parts of the body grow at an even rate, is called isometric growth.

Question 20. How do you denote the growth of an organism, in which different parts of the body grow at uneven rates?
Answer: The growth of certain organisms, where different parts of the body grow at an uneven rate, is called allometric growth.

Question 21. Which part of the human body shows the slowest rate of growth?
Answer: Human head

Question 22. Which part of the human body shows the highest rate of growth?
Answer: Human legs

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Question 23. At which age of human life, does height increase at the highest rate?
Answer: During the first three years of human life, height’ increases at the highest rate.

Question 24. At which growth phase, do thickening and ornamentation of cell wall occur in plant cells?
Answer: Phase of cell differentiation

Question 25. Which hormone becomes highly active in human adolescent males?
Answer: Testosterone

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Question 26. In which type of growth, all the organs do not increase in the same proportion?
Answer: Allometric growth

Question 27. Give an example of an organism with allometric growth.
Answer: Human

Question 28. What is a toddler?
Answer:

Toddler

A toddler is a child who learns to walk with a great cognitive, emotional and social development of 1-3 years of age.

Importance of Nutrition in Growth

Question 29. Which age of a human is called the adolescent stage.
Answer: 10-19 years

Question 30. In which phase of growth of human metabolism decreases?
Answer: Old age

Question 31. Give one example of isometric growth.
Answer: Isometric growth can be seen in fish.

Question 32. Which is the first site of growth?
Answer: Embryo

Question 33. Which type of metabolism is growth?
Answer: Anabolism

 

Chapter 2 Growth And Development Fill In The Blanks

Question 1. Due to _________, structural complexity increases in a living body.
Answer: Development

Question 2. An organism attains _________ by the process of growth and development.
Answer: Maturity

Question 3. Growth in animals occurs for a _________ period of time.
Answer: Limited

Question 4. After fertilisation, a unicellular _________ is formed.
Answer: Zygote

Question 5. During cellular differentiation, _________ cell wall is formed.
Answer: 5Secondary

Question 6. The period of human life from birth to the end of the first month is called the _________ phase.
Answer: Neonatal

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Question 7. Attaining sexual maturity is denoted as the onset of _________.
Answer: Puberty

Question 8. During the cell enlargement phase, a young cell absorbs _________ to increase its volume.
Answer: Water

Question 9. In plants, the cell layer below _________ shows cellular enlargement.
Answer: Cambium

Question 10. During the _________ period, attraction towards the opposite sex increases significantly.
Answer: 1Adolescent

Question 11. During _________a human baby learns to utter meaningful words.
Answer: Childhood

Question 12. In human females, two hormones become highly active during puberty, these are _________ and progesterone.
Answer: Oestrogen

Question 13. The age 10-19 of humans is called _________ phase.
Answer: Adolescent

Question 14. The age of 60 or more is included in _________ phase.
Answer: Old age

Question 15. The motor activities of human is developed in _________ phase.
Answer: Childhood

 

Chapter 2 Growth And Development State True Or False

Question 1. The size of all organisms changes permanently during growth.
Answer: True

Question 2. Hormones play an important role in the growth of an organism.
Answer: True

Wbbse Class X Life Science

Question 3. Human development is divided into four phases.
Answer: False

Question 4. Cell enlargement occurs by continuous intake of water and synthesis of organic matter within the cell.
Answer: True

Question 5. The number of cells increases by mitosis.
Answer: True

Question 6. The growth of any organism occurs with an increase in dry weight of the cytoplasm of all its cells.
Answer: True

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Question 7. The age between 20 to 40 years denotes adulthood.
Answer: False

Question 8. In human life, 10 to 15 years of age indicates childhood.
Answer: False

Question 9. Germ cell production in gonads starts during adolescence.
Answer: True

Question 10. Gradual loss of memory occurs during old age.
Answer: True

Question 11. The study of human development is known as gerontology.
Answer: False

 

Chapter 2 Growth And Development Match The Columns

Question 1.

Answer: 1. B, 2. A, 3. D, 4. C, 5. F, 6. E

Question 2.

Answer: 1. B, 2. A, 3. D, 4. C, 5. F, 6. E

Wbbse Class 10 Life Science Solutions

Chapter 2 Growth And Development Find The Odd One Out

Question 1. Childhood, Adulthood, Old age, Birth
Answer: Birth

Question 2. The phase of cell division, Phase of cell enlargement, Phase of cell differentiation, Cell cycle
Answer: Cell cycle

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Question 3. Rapid growth, development of sexual character, Development of sex organs, Loss of bone density
Answer: Loss of bone density

Question 4. Neonate, Adolescent, Old age, Phase of cell differentiation.
Answer: Phase of cell differentiation

 

Chapter 2 Growth And Development Fill In The Blanks By Looking At The First Pair

Question 1. Formation of new cells: Phase of cell division:: Formation of different tissues:_____________
Answer: Phase of cell differentiation

Question 2. The phase of cell enlargement: Phase of growth:: Adolescence:_____________
Answer: Phase of development

Wbbse Class 10 Life Science Solutions

Question 3. 2 months year: Childhood:: 10-19 years: _____________
Answer: Adolescence

Question 4. The onset of activity of sex hormones: Adolescence Optimum activity of sex hormones: _____________
Answer: Adulthood

Question 5. Identification of sound: Neonate:: Decrease of hearing: _____________
Answer: Old age

 

Chapter 2 Growth And Development Among The Four Concepts Given Three Of Them Belong To One Find That

Question 1. Old age, Childhood, Adulthood, Phases of development
Answer: Phases of development

Question 2. Phase of cell division, Phase of cell enlargement, Phase of cell differentiation, Phases of growth
Answer: Phases of growth

Question 3. Formation of phloem tissue, Formation of nerve tissue, Formation of muscle tissue, Phase of cell differentiation
Answer: Phase of cell differentiation

Question 4. Loss of bone density, Old age, Loss of hearing, Loss of vision
Answer: Old age

 

Chapter 2 Growth And Development Advanced Questions and Answers

Question 1. What is fascicular cambium? What is its importance during grafting?

Answer:

Fascicular cambium:

The fascicular cambium is a meristem present between the primary xylem and phloem of vascular bundles.

Importance of Fascicular cambium:

During grafting it produces secondary xylem and secondary phloem in both stock and scion. This newly formed vascular tissues mix together through which it connect the two stems.

Question 2. How does the vegetative reproduction of plants take place through layering?

Answer:

In this process, the outer epidermis of a node portion of a branch is removed to expose the vascular tissue. This portion this then covered with soil, cow dung and cloth. Watering is done at regular intervals.

After a few days, roots develop in this portion by the activity of meristem. At this stage, the branch is removed from the main plant and is planted separately.

Wbbse Class 10 Life Science Solutions

Question 3. What is parthenogenesis?

Answer:

Parthenogenesis

The process through which an offspring is formed without fertilisation from an unfertilised egg is called parthenogenesis.

Example-Wasp, are honey bees, grape plants, etc.

Question 4. What is bulbil?

Life Science Class 10 Wbbse

Answer:

Bulbil

Bulbil is a type of vegetative reproductive structure in which a round, multicellular structure develop at the axil of leaves.

Example-Dioscorea sp.

Question 5. What is an actinomorphic flower?

Answer:

Actinomorphic flower

A flower which can be cut into two equal halves through more than one plane is called an actinomorphic or regular flower.

Example-Hibiscus.

Question 6. What is the zygomorphic flower?

Answer:

Zygomorphic flower

A flower which can be cut into two equal halves through only one plane is called a zygomorphic or irregular flower.

Example-Pea flower.

Question 7. What is the type of growth in perennial woody plants?

Answer: Indefinite growth

Question 8. The annual plants dies after growing for a certain period, flowering and fruiting. What type of growth it is?

Answer: Definite growth

Wbbse Class 10 Life Science Solutions

Question 9. What is the tanner scale or tanner stage?

Answer:

Tanner scale or tanner stage

The predefined chart used to measure the physical development of a child, adolescent and mature adult is called the tanner scale or tanner stage. It is mainly used to measure secondary sexual growth, so it is also known as Sexual Maturity Rating (SMR).