CBSE · NCERT · Class 8 Science · Chapter 7

NCERT Solutions: Class 8 Science Chapter 7 - Reaching the Age of Adolescence

12 textbook Q&A12 verifiedFree Content

Chapter-wise NCERT intext questions and exercise answers for Reaching the Age of Adolescence, grounded in the official textbook.

Questions are taken verbatim from the NCERT textbook; answers were grounded against the chapter's content during generation. Items needing review are marked.
Sections in this chapter
Exercises 12
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1Exercises12 questions
Q.1What is the term used for chemical secretions of endocrine glands?v
Answer:

Hormones.

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Q.2Define adolescence.v
Answer:

Adolescence is the period of life when the body undergoes changes leading to reproductive maturity, roughly from 11 to 19 years.

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Q.3What is menstruation? Explain.v
Answer:

Menstruation is the monthly discharge of blood and the uterine lining through the vagina when the released egg is not fertilised. It is part of the menstrual cycle and begins at puberty.

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Q.4List changes in the body that take place at puberty.v
Answer:

Increase in height, change in body shape, development of reproductive organs, hair growth in armpits and pubic region, voice changes in boys, development of breasts in girls, increased sweat and oil gland activity, and emotional and mental changes.

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Q.5Prepare a table of endocrine glands and hormones secreted by them.v
Answer:

Pituitary - growth hormone; thyroid - thyroxine; pancreas - insulin; adrenal glands - adrenaline; testes - testosterone; ovaries - estrogen.

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Q.6What are sex hormones? Why are they named so? State their function.v
Answer:

Sex hormones are hormones produced by testes and ovaries. They are named so because they control development of male and female secondary sexual characters and reproductive functions. Testosterone acts in boys; estrogen acts in girls.

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Q.7aAdolescents should be careful about what they eat becausev
  1. i. proper diet develops their brains
  2. ii. proper diet is needed for rapid body growth
  3. iii. adolescents feel hungry all the time
  4. iv. taste buds are well developed
Answer:

(ii) proper diet is needed for rapid body growth.

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Q.7bReproductive age in women starts when theirv
  1. i. menstruation starts
  2. ii. breasts start developing
  3. iii. body weight increases
  4. iv. height increases
Answer:

(i) menstruation starts.

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Q.7cThe right meal for adolescents consists ofv
  1. i. chips, noodles, coke
  2. ii. chapati, dal, vegetables
  3. iii. rice, noodles and burger
  4. iv. vegetable cutlets, chips and lemon drink
Answer:

(ii) chapati, dal, vegetables.

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Q.8Write notes on Adam's apple, secondary sexual characters and sex determination in unborn baby.v
Answer:

Adam's apple is the protruding voice box seen more clearly in boys after puberty. Secondary sexual characters are features such as facial hair in boys and breast development in girls. Sex of a baby depends on whether the fertilising sperm carries an X chromosome or a Y chromosome; XX gives a girl and XY gives a boy.

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Q.9Solve the word-game clues for adolescence terms.v
Answer:

Across: Adam's apple, endocrine, pituitary, hormones, insulin, estrogen. Down: testosterone, thyroid, adolescence, target site, larynx, puberty.

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Q.10What conclusion can be drawn from height-age graphs for boys and girls?v
Answer:

Both boys and girls grow rapidly during adolescence. Girls usually grow faster earlier, around 12 years, while boys catch up and generally become taller by about 20 years.

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