NCERT Exemplar Class 8 Science Solutions for Chapter 9 - Reproduction In Animals

NCERT Exemplar Solutions Class 8 Science Chapter 9 – Free PDF Download

The NCERT Exemplar for Class 8 Science Chapter 9 Reproduction in Animals is a perfect tool for the CBSE Class 8 examination. This Exemplar solution will help you learn concepts comprehensively by strengthening your basics. By solving these Exemplar questions, you will be able to clear the doubts that can come to your mind. The NCERT Exemplar for Class 8 Science Chapter 9 will benefit you immensely, as the solutions help you understand the topics in-depth. Besides, this will aid in learning advanced topics. This exemplar has a variety of questions and answers which you can rely on for your exam preparation.

The chapter Reproduction in Animals is about learning the different modes of reproduction, like sexual reproduction and asexual reproduction. In the sexual reproduction section, students will learn about the male reproductive organs, female reproductive organs and fertilisation. In the asexual reproduction section, they will learn about budding and binary fission. To score good marks in the exam, students are advised to solve the questions from the NCERT Exemplar for Class 8 Chapter 9 Reproduction in Animals. Visit the below link to download the NCERT Exemplar for Class 8 Chapter 9.

Download the PDF of NCERT Exemplar Class 8 Science Solutions for Chapter 9 – Reproduction in Animals

Access Answers to the NCERT Exemplar Class 8 Science Chapter 9 – Reproduction in Animals

Multiple Choice Questions

1. Sets of reproductive terms are given below. Choose the set that has an incorrect combination.

(a) sperm, testis, sperm duct, penis

(b) menstruation, egg, oviduct, uterus

(c) sperm, oviduct, egg, uterus

(d) ovulation, egg, oviduct, uterus

Soln:

(c) sperm, oviduct, egg, uterus

Explanation:

Sperm is male gamete, the egg is female gamete, oviduct and uterus are part of the female reproductive system. Hence option c) is an incorrect combination.

2. In humans, the development of the fertilised egg takes place in the

(a) ovary

(b) testis

(c) oviduct

(d) uterus

Soln:

Answer is (d) uterus

Explanation:

The development of the fertilised egg takes place in the uterus. Embryo gets embedded in the wall of the uterus for development by implantation.

3. In the list of animals given below, the hen is the odd one out.

The reason for this is

(a) it undergoes internal fertilisation.

(b) it is oviparous.

(c) it is viviparous.

(d) it undergoes external fertilisation.

Soln:

Answer is (b) it is oviparous

Explanation:

The hen is oviparous, it lays the egg and the young one gets hatched later.

Rest of the animals provided are viviparous. They give birth to young ones after they are developed completely.

4. Animals exhibiting external fertilisation produce a large number of gametes. Pick the appropriate reason from the following.

(a) The animals are small in size and want to produce more offsprings.

(b) Food is available is plenty of water.

(c) To ensure a better chance of fertilisation.

(d) Water promotes the production of a large number of gametes.

Soln:

Answer is (c) To ensure a better chance of fertilization

Explanation:

Because they release gametes in water chances of getting washed away by water, wind and rain are more. Hence To ensure better chance of fertilisation. A large number of gametes are produced by Animals exhibiting external fertilization.

5. Reproduction by budding takes place in

(a) hydra

(c) paramecium

(b) amoeba

(d) bacteria

Soln:

Answer is (a) hydra

Explanation:

Paramecium, Amoeba and bacteria reproduce by binary fission. Hydra reproduces by budding where a bud detaches from the parent which grows into a complete organism.

6. Which of the following statements about reproduction in humans is correct?

(a) Fertilisation takes place externally.

(b) Fertilisation takes place in the testes.

(c) During fertilisation, egg moves towards the sperm.

(d) Fertilisation takes place in the human female.

Soln:

(d) Fertilisation takes place in the human female.

Explanation:

Male gametes are introduced into a female’s body through the vagina. Sperm reach uterus through the oviduct. At uterus, egg gets fertilized by sperm to form a zygote.

7. In human beings, after fertilisation, the structure which gets embedded in the wall of uterus is

(a) ovum

(b) embryo

(c) foetus

(d) zygote

Soln:

Answer is (b) embryo

Explanation:

Egg fuses with sperm to form the zygote which will divide to form a clump of hundreds of cells which form the embryo. The process of moving down embryo from oviduct into the uterus is called as implantation.

8. Aquatic animals in which fertilisation occurs in water are said to be:

(a) viviparous without fertilisation.

(b) oviparous with external fertilisation.

(c) viviparous with internal fertilisation.

(d) oviparous with internal fertilisation.

Soln:

Answer is (b) oviparous with external fertilisation.

Explanation:

Aquatic animals lay eggs and release sperms into the water for fertilization to take place. Young one is formed outside the body hence it is called external fertilization.

9. After fertilisation, the resulting cell which gives rise to a new individual is the

(a) embryo

(b) ovum

(c) foetus

(d) zygote

Soln:

Answer is (d) zygote

Explanation:

The zygote is the beginning of the formation of a new individual. All the multicellular organisms start their life from single-celled zygote.

10. In human beings, the correct sequence of events during reproduction is

(a) gamete formation, fertilisation, zygote, embryo

(b) embryo, zygote, fertilisation, gamete formation

(c) fertilisation, gamete formation, embryo, the zygote

(d) gamete formation, fertilisation, embryo, the zygote

Soln:

Answer is (a) gamete formation, fertilisation, zygote, embryo

Explanation:

In humans, male gametes fuse with female gametes to fertilise in the female ovary. Fertilised sperm and egg form zygote which will divide repeatedly to form the embryo.

Very Short Answer Questions

11. Although 2 cells called gametes fuse, the product formed is a single cell called the zygote. Justify.

Soln:

During fertilization, only the nucleus of the sperm gets implanted into the uterus to form a zygote. Then sperm degenerates. Hence fused cell is called gamete.

Stages in the lifecycle of silkworm are given below. Write them in sequential order.

12. Stages in the lifecycle of silkworm are given below. Write them in sequential order.

Soln:

a)Egg.

b)Pupa.

c)Silkmoth.

d)Silkworm.

13. What is the importance of reproduction?

Soln:

Reproduction ensures the continuation of species from generation to generation.

14. In markets, eggs of birds are available but never eggs of dogs. Why?

Soln:

Because the dog is viviparous. It does not lay an egg. It gives birth to a new one.

15. The eggs of frogs do not have shells for protection, yet they are safe in the water. How?

Soln:

Jelly like covering on the eggs give the protection Hence frog’s eggs are safe in the water.

Short Answer Questions

16. Fill up the blanks with the terms given below:

Amoeba is a ___________ celled organism. It reproduces by ___________ reproduction. The process of reproduction begins by the division of its ___________ into two. This is followed by the division of its ___________ into two. This type of reproduction is called ___________ fission.

Soln:

Amoeba is a single-celled organism. It reproduces by asexual reproduction. The process of reproduction begins with the division of its nucleus into two. This is followed by the division of its body into two. This type of reproduction is called binary fission.

17. The term metamorphosis is not used while describing human development. Why?

Soln:

Because body parts of humans will be present by birth. Whereas in metamorphosis parts of adults are different from the young ones.

18. Mother gives birth to a baby but the baby has characters of both parents. How is this possible?

Soln:

Though the mother gives birth to baby fertilization involves the fusion of gametes from both the parents. Hence character is obtained by both the parents.

19. How is reproduction in hydra different from that in amoeba?

Soln:

Hydra reproduces by budding where a bud detaches from the parent which grows into a complete organism. Whereas amoeba reproduces by binary fission. The process of reproduction begins with the division of its nucleus into two. This is followed by the division of its body into two.

20. State whether the following statements are True or False. If false, correct the statement:

(a) External fertilisation can occur both in water and on land.

(b) The eggs of fish are covered by hard shells for protection.

(c) The human egg has a head, middle piece and tail.

(d) In adult human females, a single mature egg is released into an oviduct every month.

Soln:

1. False- External fertilisation can occur only in water.
2. False- eggs of fish are covered by jelly-like substance for protection.
3. False- Human sperm has a head, middle piece and tail.
4. True

21. Why do only male gametes have a tail?

Soln:

Because sperm need to be motile to reach the non-motile egg in the ovary of the female.

22. What does Fig. 9.1 represent?

Soln:

The figure shows Binary fission of amoeba with a dividing nucleus.

23. Observe the figure given as Fig. 9.2 and answer the questions that follow.

(a) Label A and B.

(b) Identify the process.

(c) What happens during this process and what is formed?

Soln:

(a) A-sperm; B-ovum (egg)

(b) Fertilisation

(c) Sperm nucleus fuses with the egg nucleus to form the zygote.

Long Answer Questions

24. How can we say that fish exhibits external fertilisation?

Soln:

Female fish releases eggs into the water and male fish releases sperm into the water. Sperm swim randomly in water to reach the egg. The nucleus of the sperm reaches the egg and fuses to form the zygote. Since fertilization takes place externally. It is called external fertilization.

25.

After observing Fig. 9.3 answer the following.

a) Read the following statements and label them in the figure:

1. The part which produces female gametes.
2. The part where the development of the baby takes place.
3. The part through which the developing embryo passes to reach the uterus.

1. Ovary
2. Uterus
3. Oviduct

b) Explain the future development of the embryo that would take place after it gets embedded in the uterus.

Soln:

Developing embryo gets embedded in the wall of the uterus for further development. The embryo continues to develop in the uterus. It gradually develops body parts such as hands, legs, head, eyes, ears etc. The stage of the embryo in which all the body parts can be identified is called a foetus (Fig. 9.9). When the development of the foetus is complete, the mother gives birth to the baby.

26. Hens and frogs are both oviparous exhibiting different types of fertilisation. Explain.

Soln:

In Hens internal fertilisation takes place. The fertilised egg develops inside the female body but the development of chick from the embryo takes place outside the body.

On the other hand in frogs both fertilisation and development of zygote to an embryo and young ones occurs outside the body.

27. Observe the following figures.

1. Identify the stages a to d in Fig. 9.4 during the development of the human baby.
2. Arrange the stages in the correct sequence of development.
3. Explain the development that takes place in any one stage.

Soln:

(i) The stages during the development of the human baby:

(a) Embedding of the embryo in the uterus.

(b) Fertilisation.

(c) Zygote formation and development of an embryo from the zygote.

(d) Zygote showing fusion of nuclei.

(ii) The correct sequence of development is:

(c) Zygote formation and development of an embryo from.

(b) Fertilisation.

(d) Zygote showing fusion of nuclei.

(a) Embedding of the embryo in the uterus.

(iii) Zygote formation

The sperm and the egg nuclei fuse to form a single nucleus resulting in the formation of a fertilised egg or zygote.

As Biology has many concepts to grasp, students often face difficulty in memorising them. To ease your understanding, BYJU’S has come up with an innovative learning approach to help you learn and memorise Biology concepts. For all chapter-wise NCERT Solutions, Exemplar, previous years’ question papers, sample papers, video and animation lessons, download BYJU’S – The Learning App.