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NCERT Solutions for Class 8 Science Chapter 7 Reaching the Age of Adolescence will assist you in scoring more marks. This includes the textbook and their solutions for Reaching the Age of Adolescence Chapter 7 of Class 8 Science, which is made in adherence to the updated syllabus 2023 released by CBSE.
Our solutions offer ample material to help students build a strong foundation and improve their understanding of the subject.
On this page, you will find all the NCERT Solutions for Class 8 Science Chapter 7 Reaching the Age of Adolescence which includes detailed exercise-based solutions. These NCERT Solutions for Class 8 Science are downloadable and easy to access. Our Science experts have meticulously developed these solutions to support students in preparing for their Class 8 exams.
NCERT Solutions for Class 8 Science Chapter 7 Reaching the Age of Adolescence
Reaching the Age of Adolescence Class 8 Science NCERT Textbook Questions
Exercise Questions
1. What is the term used for chemical secretions of endocrine glands responsible for changes taking place in the body?
Solution: Hormones.
2. Define adolescence.
Solution:
The period of life that comes between the beginning of adulthood and puberty is called adolescence. In this period, the body undergoes different changes leading to reproductive maturity.The period of adolescence is normally 11 years to 19 years, but it may differ from person to person.
3. What is menstruation? Explain.
Solution:
The cycle of Changes that occur in female reproductive system once in every 28-30 days is called menstrual cycle. At the onset of puberty, generally around 10 to 12 years of age, the eggs known as ova start to mature. One egg becomes ready and is released from one of the ovaries approximately every 28 to 30 days. During this time, the lining of the uterus thickens to prepare for the possible arrival of a fertilized egg. If fertilization occurs, the egg begins to develop, resulting in pregnancy. However, if fertilization does not happen, the released egg and the thickened uterine lining, along with its blood vessels, are shed from the body. This shedding leads to bleeding in women known as menstruation, which occurs approximately every 28 to 30 days.
4. List changes in the body that take place at puberty.
Solution:
Changes that takes place during puberty are different for boys and girls. Some changes are listed below as follows-
– Sudden changes in height of both boys and girls.
– Change in body shape. In boys, the muscles develop and shoulders become broad and it girls there is enlargement of breasts, deposition of fat around the hips etc.
– Change in voice. In boys, it becomes deep and harsh and in girls it becomes high pitched.
– Increased activity of sweat and sebaceous glands.- Hair start growing in different parts of the body in both boys and girls.
– Reproductive organ develops and boys and girls become capable of reproduction.
– Changes in secondary sexual characters in both male and female.
– In girls, Menstruation starts.
5. Prepare a Table having two columns depicting names of endocrine glands and hormones secreted by them.
Solution:
| S.No. | Endocrine Glands | Hormones Secreted |
| 1. | Pituitary Gland | Growth Hormones |
| 2. | Adrenal Glands | Adrenaline |
| 3. | Pancreas | Insulin |
| 4. | Thyroid | Thyroxine |
| 5. | Testes | Testosterone |
| 6. | Ovaries | Estrogen, Progesterone |
6. What are sex hormones? Why are they named so? State their function.
Solution:
The hormones that stimulate the secondary sexual characters are called sex hormones. They are called so because they regulate the growth and function of reproductive organs and also control the sexual activities.
Function of Sex Hormones-
- In males, testes produce the male hormone testosterone, which helps in controlling the primary and secondary sexual characters in males and is also responsible for the production of sperms.
- In females, ovaries secrete estrogen and progesterone which controls the secondary sexual characters in females, appearance of mammary glands, regulation of menstruation cycle, pregnancy etc.
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.
Solution: (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.
Solution: (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.
Solution: (ii) chapati, dal, vegetables.
8. Write notes on—
(a) Adam’s apple.
(b) Secondary sexual characters.
(c) Sex determination in the unborn baby
Solution:
(a) Adam’s apple- The growing voice box in boys can be seen as a protruding part of the throat ( larynx ) is known as the Adam’s apple. During puberty, a change in the voice of boys and girls takes place due to increase in the size of the voice box or larynx. In Boys, when the voice box protrudes out, it makes their voice hoarse and in girls its hardly visible due to its small size.
(b) Secondary sexual characters– Secondary sexual characteristics are the traits that emerge during the onset of puberty and help in distinguishing male and female.
Characteristics observed in males include a deepening of the voice, the development of facial hair (such as a beard), broadening of the chest, and the growth of pubic hair.
In females, secondary sexual characteristics include the commencement of the menstrual cycle, breast growth, and the growth of pubic hair.
(b) Sex determination in the unborn baby– The sex determination of an unborn baby depends upon the pair of sex chromosomes that are present in the cells of the baby. All human beings have 23 pairs of chromosomes in the nuclei of their cells. Two chromosomes out of these are sex chromosomes. A female has two X chromosomes, while a male has one X and one Y chromosome. The gametes (egg and sperm) have only one set of chromosomes. The unfertilised egg always has one X chromosome.
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
Solution:
Across
3. Adam’s apple
4. Endocrine
7. Pituitary
8. Hormone
9. Insulin
10. Estrogen
Down
1. Testosterone
2. Thyroid
3. Adolescence
5. Target Site
6. Larynx
7. Puberty
Summary
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