CBSE Class 8 Science Reaching the Age of Adolescence VBQs

Choose the correct option.

(a) Adolescents should be careful about what they eat, because:
(i) proper diet develops their brains.
(ii) proper diet is needed for the rapid growth taking place in their body. (✓)
(iii) adolescents feel hungry all the time.
(iv) taste buds are well developed in teenagers.
Answer : B

(b) Reproductive age in women starts when their
(i) menstruation starts.(✓)
(ii) breasts start developing.
(iii) body weight increases.
(iv) height increases.
Answer : A

(c) The right meal for adolescents consists of
(i) chips, noodles, coke.
(ii) chapati, dal, vegetables. (✓)
(iii) rice, noodles and burger.
(iv) vegetable cutlets, chips and lemon drink.
Answer : B

Question. List changes in the body that take place at puberty.
Answer : The onset of puberty brings about:
(i) Growth of the reproductive organs which begin to function.
(ii) Hair growth at various places of the body. Breasts develop in girls and facial hairs appear in boys.
(iii) Voice of the boys becomes hoarse as voice box enlarges during adolescence.

Question. What is the term used for secretions of endocrine glands responsible for changes taking place in the body?
Answer : Hormones.

Question. What are sex hormones? Why are they named so? State their function.
Answer : The chemical substances produced by the sex organs are called sex hormones. They are named so because they control the sexual activities and are secreted by males and females separately.
Estrogen: This hormone is responsible for the development of secondary sexual characters in females like enlargement of breasts, development of female reproductive organs etc.
Testosterone: this hormone brings the secondary sex character in boys such as the growth of beard, the voice becomes hoarse, development of the reproductive organs etc.

Question. Define adolescence.
Answer : The period of life, when the body undergoes changes, leading to reproductive maturity, is called adolescence. The period of adolescence is normally 11 years to 19 years.

Question. Prepare a table having two columns depicting names of endocrine glands and hormones secreted by them.
Answer :

Question. What is menstruation? Explain.
Answer : The cyclic flow of blood and mucus along with inner lining of uterus in case of not fertilization of egg from the female body is called menstruation. Each month uterus prepares itself to receive the fertilized egg. If fertilization do not occurs the inner ling breaks away and comes out through vagina for 3-5 days.

Question. Write notes on—
(a) Adam’s apple.
(b) Secondary sexual characters.
(c) Sex determination in the unborn baby.
Answer : (a) Adam’s apple- At puberty, the voice box or the larynx begins to grow. The growing voice box in boys can be seen a protruding part of the throat called Adam’s apple.
(b) Secondary sexual characters- Those characters which are visible more apparently and help in distinguishing a male from a female are called secondary sexual characters. For example, in girls, breasts and in boys facial hairs i.e., moustache and beard.
(c) Sex determination in the unborn baby- Human beings have 23 pairs of chromosome. One pair of male (XY) and one pair of chromosome in female (XX) are called sex chromosome. When the sperm containing Y chromosome fuse with egg the sex of baby is male and when X chromosome containing sperm fertilse the egg the sex of baby is female.

Question. Word game : Use the clues to work out the words.
Across
3. Protruding voice box in boys -- Adam’s apple
4. Glands without ducts -- Endocrine
7. Endocrine gland attached to brain -- Pituitary
8. Secretion of endocrine glands -- Hormone
9. Pancreatic hormone -- Insulin
10. Female hormone -- Estrogen
Down
1. Male hormone -- Testosterone
2. Secretes thyroxine -- Thyroid
3. Another term for teenage -- Adolescence
5. Hormone reaches here through blood stream -- Target site
6. Voice box -- Larynx
7. Term for changes at adolescence – Puberty.