Reaching the Age of Adolescence important questions

NCERT Solutions for Class 8th Science Chapter 9 Reaching the Age of Adolescence Questions and answers based on the latest syllabus of CBSE and JKBOSE NCERT Books

Reaching the Age of Adolescence

Exercises

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

• Hormones.

2. Define adolescence?

• Adolescence is the period of life when a child develops into an adult. This period generally ranges from 11 to 19 years of age.

3. What is menstruation? Explain.

• Menstruation is the monthly shedding of the uterine lining in females, which occurs if the egg released during the ovulation period is not fertilized. This cycle is approximately 28 days long.

4. List changes in the body that take place at puberty?

• Development of secondary sexual characteristics such as the growth of body hair, deepening of the voice in boys, and development of breasts in girls.
• Increase in height and weight.
• Development of reproductive organs.
• Increased activity of sebaceous and sweat glands, leading to acne and body odor.

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

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

• Sex hormones are hormones that are responsible for the development of secondary sexual characteristics and reproductive functions. They are named sex hormones because they regulate the functions of the sex organs.
• Functions:
  • Testosterone: Develops male characteristics like a deeper voice, facial hair, and muscle mass.
  • Estrogen and Progesterone: Develop female characteristics like breast development and regulation of the menstrual cycle.

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.

• Correct answer: (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.

• Correct answer: (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.

• Correct answer: (ii) chapati, dal, vegetables.

8. Write notes on—

(a) Adam’s apple:

• Adam’s apple is a cartilage lump present in the throat, which is more prominent in boys during and after puberty. It is the result of the growth of the larynx (voice box).

(b) Secondary sexual characters:

• These are features that appear during puberty, distinguishing the two sexes but are not directly involved in reproduction. Examples include facial hair and a deeper voice in boys, and breast development in girls.

(c) Sex determination in the unborn baby:

• Sex determination is a process by which the sex of an unborn baby is decided at the time of fertilization. It depends on the combination of sex chromosomes received from the parents. An XY combination results in a male, while an XX combination results in a female.

9. 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
5. Endocrine gland attached to the brain – Pituitary
6. Secretion of endocrine glands – Hormone
7. Pancreatic hormone – Insulin
8. Female hormone – Estrogen

Down:

1. Male hormone – Testosterone
2. Secretes thyroxine – Thyroid
3. Another term for teenage – Adolescence
4. Hormone reaches here through bloodstream – Target
5. Voice box – Larynx
6. Term for changes at adolescence – Puberty

10. The table below shows the data on likely heights of boys and girls as they grow in age. Draw graphs showing height and age for both boys and girls on the same graph paper. What conclusions can be drawn from these graphs?

• Graph Interpretation:
• Initially, boys and girls have similar growth patterns.
• During adolescence (around 12-16 years), girls typically grow faster than boys.
• By adulthood, boys generally surpass girls in height.

These solutions and notes provide a detailed understanding of the topics covered in the chapter “Reaching the Age of Adolescence,” helping students grasp the concepts more effectively.