Active Science Solutions for Class 8 Science Chapter 8 Reproduction In Animals are provided here with simple step-by-step explanations. These solutions for Reproduction In Animals are extremely popular among class 8 students for Science Reproduction In Animals Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Active Science Book of class 8 Science Chapter 8 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Active Science Solutions. All Active Science Solutions for class 8 Science are prepared by experts and are 100% accurate.

Page No 116:

Question 1:

Which of the following is true about asexual reproduction?
(a) involves the fusion of gametes
(b) special cells are required
(c) involves only one parent
(d) all the above

Answer:

(c) Involves only one parent

Asexual reproduction involves only one parent, and no special cells are required for it.

Page No 116:

Question 2:

The growing foetus draws its nutrition from the
(a) placenta.
(b) cervix.
(c) uterus.
(d) fallopian tubes.

Answer:

(a) placenta

The placenta connects the foetus to the mother's body, and through it, the foetus draws its nutrition.

Page No 116:

Question 3:

The starting of the menstrual cycle is termed
(a) menopause.
(b) menstruation.
(c) puberty.
(d) menarche.

Answer:

(d) menarche

The starting of the menstrual cycle is termed menarche. It starts in girls 10-12 years of age.

Page No 116:

Question 4:

Fertilisation takes place in the
(a) fallopian tube.
(b) uterus.
(c) ovary.
(d) cervix.

Answer:

(a) fallopian tube

Fertilisation takes place in the oviducts, also called the fallopian tubes.

Page No 116:

Question 5:

Secondary sexual changes occur:
A. during puberty.
B. after menopause.
C. along with external changes.
D. only in males.

(a) Only A is correct.
(b) Both A and C are correct.
(c) Only C is correct.
(d) Both B and C are correct.

Answer:

(b) Both A and C are correct.

Secondary sexual changes occur during puberty, which is associated with external changes such as the development of mammary glands in girls, voice change in boys, and the growth of thick hair in both boys and girls.



Page No 117:

Question 6:

To keep the population in check
(a) birth control measures should be followed.
(b) the size of the family should be limited.
(c) the age of marriage should be increased.
(d) all the above

Answer:

(d) all the above

The population can be kept in check by increasing the age of marriage and implementing birth control measures to limit the size of families.

Page No 117:

Question 7:

How many sperms are needed to fertilise the egg?
(a) one
(b) two
(c) more the two
(d) one million

Answer:

(a) One

Only one sperm is needed to fertilise an egg.

Page No 117:

Question 8:

Gestation does not follow
(a) if the egg is fertilised.
(b) if the egg is not fertilised.
(c) if the embryo has been implanted.
(d) none of the above.

Answer:

(b) if the egg is not fertilised

If the egg is not fertilised, then a zygote is not formed and gestation does not follow.

Page No 117:

Question 9:

Which of the following does not reproduce asexually?
(a) bacteria
(b) Amoeba
(c) fish
(d) yeast

Answer:

(c) fish

Fish reproduce sexually.

Page No 117:

Question 10:

Which of the following statements is not true?
(a) Earthworms are hermaphrodites.
(b) Young ones of animals which have external fertilisation receive little or no parental care.
(c) If the egg is not fertilised, it is thrown out of the body along with the lining of the uterus as menstrual flow.
(d) Sex organs are formed at puberty.

Answer:

(d) Sex organs are formed at puberty.

Sex organs are formed in the foetus.

Page No 117:

Question 11:

Explain the following terms:
hormone, endocrine gland, ovulation, fertilisation, menstruation, sexual reproduction

Answer:

Hormones are chemical substances produced by different glands in the body. They control the functioning of the body.

Endocrine glands are the glands that produce hormones.

Ovulation is the release of ova from the ovary.

Fertilisation is the fusion of a sperm and an ovum.

Menstruation is the flow of blood and tissues from the vagina in girls, which occurs every month after they attain puberty. Menstruation occurs only when the egg has not been fertilised by a sperm.

Sexual reproduction is the mode of reproduction that requires two individuals, i.e., a male and a female.

Page No 117:

Question 12:

List three secondary sexual changes that take place at puberty in boys.

Answer:

Three secondary sexual changes that take place in boys at puberty are as follows.

(a) Growth of hair on the face, pubic region and armpits

(b) Deepening of the voice

(c) Enlargement of the penis and the scrotum

Page No 117:

Question 13:

List three secondary sexual changes that take place in girls during puberty.

Answer:

Three secondary sexual changes that take place in girls at puberty are as follows.

(a) Enlargement of the breasts

(b) Growth of hair in the pubic region and the armpits.

(c) Widening of the pelvic girdle

 

Page No 117:

Question 14:

Explain how sperm from the father determines the sex of a child.

Answer:

A female produces eggs with only the X chromosome. But males produce sperms that can have either the X or the Y chromosome. If a sperm carrying the Y chromosome fuses with the egg, then the sex of child will be male (XY). If a sperm carrying the X chromosome fuses with the egg, then the sex of child will be female (XX).

Page No 117:

Question 15:

Why do animals that reproduce through internal fertilisation produce fewer eggs than those that reproduce through external fertilisation?

Answer:

In external fertilisation, the gametes are released outside the body in water, which increases the chances of loss of the gametes. To increase the chances of fertilisation, gametes are produced in large numbers. But, in internal fertilisation, the eggs are protected in the female body, and thus fewer eggs are produced as the chances of fertilisation are high.

Page No 117:

Question 16:

Differentiate between the following pairs of words.
(a) external and internal fertilisation
(b) sexual and asexual reproduction
(c) ovulation and fertilisation
(d) menopause and menarche

Answer:

(a)

External fertilisation Internal fertilisation
The gametes are released outside the body and fertilisation takes place outside the body. The gametes fuses within the body of the female parent.
For example, frogs use external fertilisation. For example, humans use internal fertilisation.

(b)
Sexual reproduction Asexual reproduction
It requires two parents and special cells called gametes. It involves only one parent.
For example, humans use sexual reproduction. For example, amoebas use asexual reproduction.

(c)
 Ovulation Fertilisation
It is release of ova or eggs from the ovary. It is the fusion of male and female gametes.

(d)
Menopause Menarche
It marks the stoppage of the menstrual cycle. It marks the start of the menstrual cycle.
It occurs at the age of 45-50 years. It occurs at the age of 10-12 years.

Page No 117:

Question 17:

List some reasons for the increase in the population of our country.

Answer:

The reasons for the increase in the population of our country are as follows.

  • Large family size and lack of family planning
  • Frequent pregnancies
  • Lack of education, due to which people do not know about birth control measures and the importance of family planning

Page No 117:

Question 18:

Draw a labelled diagram of the female reproductive system.

Answer:



       The female reproductive system

Page No 117:

Question 19:

What are the two products of the testes?

Answer:

The two products of the testes are sperms and the male sex hormone called testosterone.

Page No 117:

Question 20:

Which one of the following shows the correct sequence in the description of the menstrual cycle?
(a) thickening of the uterine lining, release of blood and tissue, ovulation, breakdown of uterine lining
(b) release of blood and tissue, breakdown of uterine lining, thickening of the uterine living, ovulation.
(c) ovulation, release of blood and tissue, breakdown of uterine lining, thickening of the uterine lining
(d) ovulation, thickening of the uterine lining, breakdown of uterine lining, release of blood and tissue

Answer:

(d) Ovulation, thickening of the uterine lining, breakdown of uterine lining, release of blood and tissue

During ovulation, an ovum is released, which results in the thickening of the uterine, to enable it to receive the fertilised ovum. If the ovum does not get fertilised, the uterine lining breaks, and blood and tissue are released from the vagina.



View NCERT Solutions for all chapters of Class 8