Ncert solutions science class 8 Solutions for Chapter 9 reproduction in animals

Each sperm is a single cell. (T/F)

A tadpole develops into an adult frog by the process of

An embryo is made up of a single cell. (T/F)

Oviparous animals give birth to young ones. (T/F)

Internal fertilisation occurs

Binary fission is a method of asexual reproduction. (T/F)

Amoeba reproduces by budding. (T/F)

External fertilisation takes place in frog. (T/F)

Q1) Explain the importance of reproduction in organisms.

Explain the importance of reproduction in organisms.

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

Describe the process of fertilisation in human beings.

Q2) Describe the process of fertilisation in human beings.

In humans, the development of a fertilised egg takes place in the

(a) ovary

(b) testis

(c) oviduct

(d) uterus

Choose the most appropriate answer.

(a) Internal fertilisation occurs

(i) in female body.

(ii) outside female body.

(iii) in male body.

(iv) outside male body.

(b) A tadpole develops into an adult frog by the process of

(i) fertilisation

(ii) metamorphosis

(iii) embedding

(iv) budding

(c) The number of nuclei present in a zygote is

(i) none

(ii) one

(iii) two

(iv) four

Q3) Choose the most appropriate answer.

(a) Internal fertilisation occurs

(i) in female body.

(ii) outside female body.

(iii) in male body.

(iv) outside male body.

(b) A tadpole develops into an adult frog by the process of

(i) fertilisation (ii) metamorphosis (iii) embedding (iv) budding

(c) The number of nuclei present in a zygote is

(i) none (ii) one (iii) two (iv) four

In the list of animals given below, 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.

Indicate whether the following statements are True (T) or False (F).

(a) Oviparous animals give birth to young ones. ( )

(b) Each sperm is a single cell. ( )

(c) External fertilisation takes place in frog. ( )

(d) A new human individual develops from a cell called gamete. ( )

(e) Egg laid after fertilisation is made up of a single cell. ( )

(f) Amoeba reproduces by budding. ( )

(g) Fertilisation is necessary even in asexual reproduction. ( )

(h) Binary fission is a method of asexual reproduction. ( )

(i) A zygote is formed as a result of fertilisation. ( )

(j) An embryo is made up of a single cell. ( )

Q4) Indicate whether the following statements are True (T) or False (F).

(a) Oviparous animals give birth to young ones. ( )

(b) Each sperm is a single cell. ( )

(c) External fertilisation takes place in frog. ( )

(d) A new human individual develops from a cell called gamete. ( )

(e) Egg laid after fertilisation is made up of a single cell. ( )

(f) Amoeba reproduces by budding. ( )

(g) Fertilisation is necessary even in asexual reproduction. ( )

(h) Binary fission is a method of asexual reproduction. ( )

(i) A zygote is formed as a result of fertilisation. ( )

(j) An embryo is made up of a single cell. ( )

Animals exhibiting external fertilization 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 in plenty of water.

(c) To ensure a better chance of fertilization.

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

Reproduction by budding takes place in

(a) hydra

(c) paramecium

(b) amoeba

(d) bacteria

Give two differences between a zygote and a foetus.

Q5) Give two differences between a zygote and a foetus.

Q6) Define asexual reproduction. Describe two methods of asexual reproduction in animals.

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.

Define asexual reproduction. Describe two methods of asexual reproduction in animals.

Q7) In which female reproductive organ does the embryo get embedded?

In which female reproductive organ does the embryo get embedded?

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

(a) ovum

(b) embryo

(c) foetus

(d) zygote

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.

Q8) What is metamorphosis? Give examples.

What is metamorphosis? Give examples.

Differentiate between internal fertilisation and external fertilisation

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

(a) embryo

(b) ovum

(c) foetus

(d) zygote

Q9) Differentiate between internal fertilisation and external fertilisation.

Complete the crossword puzzle using the hints given below.

Across

1. The process of the fusion of the gametes.

6. The type of fertilisation in hen.

7. The term used for bulges observed on the sides of the body of hydra.

8. Eggs are produced here.

Down

2. Sperms are produced in these male reproductive organs.

3. Another term for in vitro fertilisation.

4. These animals lay eggs.

5. A type of fission in amoeba

Q10) Complete the crossword puzzle using the hints given below.

Across

1. The process of the fusion of the gametes.
2. The type of fertilisation in hen.
3. The term used for bulges observed on the sides of the body of hydra.
4. Eggs are produced here.

Down

5. Sperms are produced in these male reproductive organs.
6. Another term for in vitro fertilisation.
7. These animals lay eggs.
8. A type of fission in amoeba.

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, zygote

(d) gamete formation, fertilisation, embryo, zygote

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

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

What is the importance of reproduction?

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

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

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.

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

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

How is reproduction in hydra different from that in amoeba?

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) 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.

Why do only male gametes have a tail?

What does Fig. represent?

Observe the figure given as Fig. 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?

How can we say that fish exhibits external fertilisation?

After observing Fig. answer the following.

a.

Read the following statements and label them in the figure:

(i) The part which produces female gametes.

(ii) The part where the development of the baby takes place.

(iii) The part through which the developing embryo passes to reach the uterus.

b.

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

uterus.

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

Observe the following figures.

(i) Identify the stages a to d in Fig. during the development of the human baby.

(ii) Arrange the stages in correct sequence of development.

(iii) Explain the development that takes place in any one stage.