NCERT Class VIII Science Solutions: Chapter 9-Reproduction in Animals Part 2

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Question 8:

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

  1. Viviparous without fertilisation.

  2. Oviparous with external fertilisation.

  3. Viviparous with internal fertilisation.

  4. Oviparous with internal fertilisation.

Answer: B

Question 9:

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

  1. Embryo

  2. Ovum

  3. Foetus

  4. Zygote

Answer: D

Image of Zygote

Image of Zygote

Image of Zygote

Question 10:

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

  1. Gamete formation, fertilisation, zygote, embryo

  2. Embryo, zygote, fertilisation, gamete formation

  3. Fertilisation, gamete formation, embryo, zygote

  4. Gamete formation, fertilisation, embryo, zygote

Answer: A

VERY SHORT ANSWER QUESTIONS

Question 11:

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

Answer:

During fertilisation, only the nucleus of the sperm moves into the egg cell and fuses with the egg nucleus to form the zygote. The sperm degenerates.

Image of fertilization

Image of Fertilization

Image of fertilization

Question 12:

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

Pupa, silkworm, egg, caterpiller

Answer:

Egg, caterpiller, pupa, silk moth

Question 13:

What is the importance of reproduction?

Answer:

It ensures the continuation of species generation after generation.

Question 14:

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

Answer:

Dogs do not lay eggs

Question 15:

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

Answer:

A layer of jelly covers the eggs of frog and provides protection.

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