NCERT Solutions for Class 8th Science
Chapter 10. Reaching the age of adolescence
Text Book Exercise
1. What is the term used for secretions of endocrine glands responsible for changes taking place in the body?
Answer : The term used for secretions of endocrine glands is hormoane which is responsible for various changes taking place in the body.
2. Define adolescence.
Answer : The period of life when the body undergors changes, leading to reproductive maturity, is called adolescence.
3. What is menstruation? Explain.
Answer : When the uterus receives the egg and it is fertilized, pregnacy occurs. If fertilization does not occur, the released egg and the thickened lining of the uterus along with its blood vesssels are shed off. This causes bleeding in women which is called menstruation.
4. 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 grows at various places of the body. Breasts develop in girl and facial hair (moustache and beard) apper in boys.
(iii) Voice of the boys becomes hoarse as voice box enlarges during adolescence.
5. Prepare a Table having two columns depicting names of endocrine glands and hormones secreted by them.
|Name of endocrine glands||Hormones secreted|
|Pituitary||FSH or Fillicle atimulating hormonre|
6. What are sex hormones? Why are they named so? State their function.
7. 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.
(b) Reproductive age in women starts when their
(i) menstruation starts.
(ii) breasts start developing.
(iii) body weight increases.
(iv) height increases.
(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.
8. Write notes on—
(a) Adam’s apple.
(b) Secondary sexual characters.
(c) Sex determination in the unborn baby.