NCERT Class 8 Science Chapter 10 Reaching The Age of Adolescence

NCERT Class 8 Science Chapter 10 Reaching The Age of Adolescence Solutions to each chapter is provided in the list so that you can easily browse through different chapters NCERT Class 8 Science Chapter 10 Reaching The Age of Adolescence and select need one. NCERT Class 8 Science Chapter 10 Reaching The Age of Adolescence Question Answers Download PDF. NCERT Class 8 Science Solutions.

NCERT Class 8 Science Chapter 10 Reaching The Age of Adolescence

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Also, you can read the NCERT book online in these sections Solutions by Expert Teachers as per Central Board of Secondary Education (CBSE) Book guidelines. CBSE Class 8 Science Solutions are part of All Subject Solutions. Here we have given NCERT Class 8 Science Chapter 10 Reaching The Age of Adolescence and Textbook for All Chapters, You can practice these here.

Reaching The Age of Adolescence

Chapter: 10

NCERT TEXT BOOK EXERCISES

Q. 1. What is the term used for secretions of endocrine glands responsible for changes taking place in the body?

Ans. Hormones.

Q. 2. Define adolescence.

Ans. Adolescence: The period of life, when the body undergoes changes, leading to reproductive maturity is called adolescence.

Q. 3. What is menstruation? Explain.

Ans. When egg produced by ovary does not get fertilized, it along with the thickened lining of the uterus and blood vessels get flown off out of the body every month as bleeding in women. This is called menstruation.

Q. 4. List changes in the body that takes place at puberty.

Ans. Changes taking place at puberty in boys.

(i) Height increases suddenly. The bones of legs and arms become long and make a boy tall.

(ii) Boy’s shoulders become broader and chest also becomes wider.

(iii) Muscles of the body grow more prominity.

(iv) The voice becomes hoarse. Adam’s apple a protruding part of throat is seen. They have a deep voice.

(v) They get acne and pimples on the face at this time due to the increased activities of sweat and sebaceous glands.

(vi) Male sex organs like testes and penis develop completely.

(vii) Boys develop hair on their chest, under the arms and on the pubic region.

Changes taking place at puberty in girls:

(i) Height also increases in girls but comparatively less.

(ii) The region below the waist becomes wider.

(iii) In girl’s the larynx is hardly visible from the outside. Girls have a high pitched voice.

(iv) Like boys, girls also get pimples on the face.

(v) The ovaries enlarge and eggs begin to mature.

(vi) Breasts begin to develop.

(vii) Hair grow under the arms and also on the pubic region.

Q. 5. Prepare a table having two columns depicting names of endocrine glands and hormones secreted by them.

Ans.

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

Ans. Sex hormones: These are the hormones secreted by testes in males and ovaries in females. They are named so because they are secreted by male and female sexes separately. 

Male sex hormone (testosterone): It is secreted by testes. It causes changes in boys like growth of facial hair. It also stimulates spermatogenesis.

Female sex hormone (Estrogen): It is secreted by ovaries. It controls the development of secondary sexual characters in females, appearance of mammary glands etc. It maintains pregnancy.

Q. 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.

Ans. (ii) proper diet is needed for the rapid growth taking place in their body.

(b) Reproductive age in women starts when their:

(i) menstruation starts.

(ii) breasts start developing.

(iii) body weight increases.

(iv) height increases.

Ans. (i) menstruation starts.

(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.

Ans. (ii) chapati, dal, vegetables.

Q. 8. Write notes on:

(a) Adam’s apple.

Ans. Adam’s apple: At puberty boys develop large voice box or larynx. This box in boys is seen as a protruding part of the throat called Adam’s apple.

(b) Secondary sexual characters.

Ans. Secondary sexual characters: The physical features which help to distinguish the male from the female are called secondary sexual characters.

The secondary sexual characteristics in humans are given below:

In males:

(i) Growth of public hair, beard and moustaches, hair on chest and under the arms.

(ii) Deepening of voice. 

In females:

(i) Enlargement of breasts and hips.

(ii) Appearance of pubic hair, hair under the arms.

Q. 9. Word game: Use the clues to work out the words.

Across:

3. Protruding voice box in boys.

4. Glands without ducts.

7. Endocrine gland attached to brain.

8. Secretion of endocrine glands.

9. Pancreatic hormone.

10. Female hormone.

Down:

1. Male hormone.

2. Secretes thyroxine.

3. Another term for Teenage.

5. Hormone reaches here through blood stream.

6. Voice box.

7. Term for changes at adolescence.

Ans.