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

In Class 8 Science Chapter 7: Reaching the Age of Adolescence, one learns about the growing increases in physical and hormonal changes as children grow into adolescence. In the chapter, topics include puberty, the endocrine system, secondary sexual characteristics, and reproductive health.

NCERT Solutions for Class 8 Science help students understand the answers to questions from this chapter and, hence, make it clear. The solutions are really great resources for giving a final touch to exam preparation and gaining an in-depth knowledge of the chapter.

1.0NCERT Solutions for Class 8 Science Chapter 7 PDF

Students can download NCERT Solutions for Class 8 science chapter 7 from the below table and practice it from anywhere anytime.

2.0Key Points to Remember in Chapter - Reaching the Age of Adolescence

• Puberty: The age when reproductive organs become functionally active.
• Adolescence: A period of physical and emotional changes leading to reproductive maturity (11–19 years).
• Secondary Sexual Characteristics: External changes include facial hair in boys, breast development in girls, voice changes, and body hair growth.
• Role of Hormones: Hormones like testosterone and estrogen control puberty changes, secreted by endocrine glands like the pituitary and thyroid.
• Reproductive Phase: The period of gamete production. Menarche marks the start of menstruation, while menopause ends it.
• Menstrual Cycle: Monthly uterine wall shedding if fertilization does not occur, leading to menstruation.
• Reproductive Health: Defined by WHO as emotional, physical, and social well-being during adolescence.
• Nutritional Needs: Adolescents require a balanced diet rich in proteins, vitamins, and minerals (calcium, iodine, iron).
• Personal Hygiene: Keeping the body clean from head to toe to prevent infections.

3.0NCERT Questions with Solutions Class 8 Science Chapter 7 - Detailed Solution

• What is the term used for chemical secretions of endocrine glands responsible for changes taking place in the body? Ans. Hormones
• Define adolescence. Ans. Adolescence is the period of life, when the body undergoes changes, leading to reproductive maturity.
• What is menstruation? Explain. Ans. If fertilization does not occur, the released egg and the thickened lining of the uterus along with its blood vessels are shed off. This causes bleeding in women which is called menstruation.
• List changes in the body that take place at puberty Ans. 1. Increase in height 2.Change in body shape 3.Change in voice 4.Increased activity of sweat and sebaceous gland 5.Reaching mental, intellectual and emotional maturity. 6.Development of sex organs 7.Secondary sexual characters
• Prepare a table having two columns depicting names of endocrine glands and hormones secreted by them. Ans.

• What are sex hormones? Why are they named so? State their function. Ans. The testes and ovaries secrete sex hormones. These hormones are responsible for the male and female secondary sexual characters. The male hormone or testosterone begins to be released by the testes at the onset of puberty. This causes changes in boys, for example, the growth of facial hair. Once puberty is reached in girls, ovaries begin to produce the female hormone or estrogen which makes the breasts develop. Milk secreting glands or mammary glands develop inside the breasts.
• 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. Ans. (a) (ii) Proper diet is needed for the rapid growth taking place in their body. (b) (i) Menstruation starts. (c) (ii) Chapati, dal, vegetables.
• Write notes on- (a) Adam's apple. (b) Secondary sexual characters. (c) Sex determination in the unborn baby. Ans. (a) At puberty, the voice box or the larynx begins to grow. Boys develop larger voice boxes. The growing voice boxes in boys can be seen as a protruding part of the throat called Adam's apple. (b) Secondary sexual characters: The features which help to distinguish the male from the female, are called secondary sexual characters. The reproductive organs are testes and ovaries which produce the gametes, sperm in male and ova in female. Similar secondary sexual characters in male and females: Growth of hairs under armpits and around pubic area, increased activity of sweat and sebaceous glands, oily skin and appearance of pimples, darkening in skin colour of the genital area. Secondary sexual characters in male: Widening of shoulders Deepening of voice Appearance of beard and moustaches Growth of sex organs (testes and penis) Secondary sexual characters in female: Widening of pelvis and hips High pitch voice Initiation of menstrual cycle Growth of mammary glands (breasts) Maturation of secondary sex organs like fallopian tubes, uterus (c) When a sperm containing ' X ' chromosome fertilises the egg, the zygote would have two ' X ' chromosomes and develops into a female child. If the sperm contributes a ' $Y$ ' chromosome to the egg (ovum) at fertilisation, the zygote will develop into a male child. The sex chromosomes of the father determine the sex of an unborn baby. The belief that the mother is responsible for the sex of her baby is completely wrong and to blame her for this is totally unjustified.
• 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?

Ans. Conclusion: (1) Girls are taller than boys till they reach the age of 12 years. (2) Till the age of 16 years, the height of both boys and girls remains the same. (3) After 16, both boys and girls increase in height. In general, boys are taller than girls.

• Word game: Use the clues to work out the words. Crossword puzzle

Across

• Protruding voice box in boys
• Glands without ducts
• Endocrine gland attached to brain
• Secretion of endocrine glands
• Pancreatic hormone
• Female hormone

Down

• Male hormone
• Secretes thyroxine
• Another term for teenage
• Hormone reaches here through blood stream.
• Voice box
• Term for changes at adolescence

• Ans.

Across

• Adam's apple
• Endocrine
• Pituitary
• Hormone
• Insulin
• Estrogen

Down

• Testosterone
• Thyroid
• Adolescence
• Target site
• Larynx
• Puberty

4.0How NCERT Solutions Help in Understanding Adolescence

The Reaching the Age of Adolescence Class 8 PDF NCERT Solutions explains complex concepts in a simple manner. ALLEN experts provide such elaborate and well-structured NCERT solutions to help students grasp these topics well.