NCERT Solutions for Class 8 Science Chapter 10 – Reaching the Age of Adolescence, contains solutions to various questions in Exercise for Chapter 10. At the end of the Solutions, all the keywords and Notes which are important to understand Science Chapter 10 – Reaching the Age of Adolescence, have been explained in a simple and easy to understand manner. NCERT Solutions for Class 8 help to check the concept you have learnt from detailed classroom sessions and application of your knowledge.
| Category | NCERT Solutions for Class 8 |
| Subject | Science |
| Chapter | Chapter 10 – Reaching the Age of Adolescence |
Download NCERT Solutions for Class 8 Science Chapter 10 – Reaching the Age of Adolescence
NCERT Solutions for Class 8 Science Chapter 10 – Reaching the Age of Adolescence– Solutions to Question 1 to Question 4
Question 1
What is the term used for secretions of endocrine glands responsible for changes taking place in the body?
Answer 1.
The term used is Hormones.
Question 2
Define adolescence.
Answer 2.
It is the transitional stage when the body undergoes physical and psychological development, and reaches reproductive maturity.
Question 3
What is menstruation? Explain.
Answer 3.
The reproductive phase in a woman begins around 12 years of age. During this period, the ova begins to mature with the onset of puberty. One ovum matures and is released by one of the ovaries once in about a month. During this period, the uterus thickens in order to prepare for receiving the egg. If fertilisation occurs, then it results into pregnancy of the woman. However, if it does not occur, then the thickened walls of the uterus along with the blood vessels are shed off. This is known as menstruation.
Question 4
List changes in the body that take place at puberty.
Answer 4.
The changes in the body that take place at puberty are:
- Increase in height of both boys and girls
- The shoulders and chest of boys get widened
- Voice of boys become hoarse
- In girls, the region below the waist gets widened
- Reproductive organs become active. In males, the testis start producing sperm and in females the starts producing eggs
- Both boys and girls face acne problems during puberty.
- Girls start having menstruation during the onset of puberty.
Question 5
Prepare a Table having two columns depicting names of endocrine glands and hormones secreted by them.
Answer 5.
| Endocrine Glands | Hormones Secreted |
|---|---|
| Thyroid | Thyroxine |
| Pancreas | Insulin |
| Pituitary gland | Growth Hormone |
| Testes | Testosterone |
| Adrenal Glands | Adrenalin |
| Ovary | Oestrogen |
Question 6
What are sex hormones? Why are they named so? State their function.
Answer 6.
The hormones which are responsible for helping and controlling secondary sexual characteristics are known as the sex hormones. These are called so because they help us in distinguishing between male and female.
They are produced by the testis in males known as testosterone and by the ovaries in females known as oestrogen. In males, testosterone is responsible for the growth of moustache and beard, hoarseness of voice and development of testes. In females, oestrogen is responsible for the development of breasts, regulation of the menstrual cycle and various other features.
Question 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.
(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.
Answer 7.
(a) (ii) proper diet is needed for the rapid growth taking place in their body.
(b) (i) menstruation starts
(c) (ii) chapati, dal, vegetables
Question 8
Write notes on—
(a) Adam’s apple.
(b) Secondary sexual characters.
(c) Sex determination in the unborn baby.’
Answer 8.
(a) The protruding part of the throat in boys is called Adam’s apple. It is the enlarged larynx which makes the voice of boys hoarse.
(b) Secondary sexual characters are the features which help in distinguishing between male and female such as appearance of beard and moustache and chest hair in boys and enlargement of breasts in females.
(c) The sex or gender of an unborn baby depends upon the sex chromosomes. The unfertilised egg always has a X chromosome however there can be two kinds of sperms- one carrying a X chromosome or one carrying a Y chromosome. If the X chromosomes pairs up with the unfertilised egg, the combination is XX which means female otherwise the combination is XY meaning a male child would be born.
Question 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
ANSWER
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
Question 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?
Answer 10.
The above graph and data show the relationship between the height of girls and boys. We can see that during the age of 4-8 years, girls have lower height compared to boys. However, during the adolescent period 12-15 years the girls show a sudden increase in height during puberty and become taller than boys. Later on, the height of both the male and females reach to a balanced state.
Topics Covered in Chapter 10 Reaching the Age of Adolescence Class 8 Science :-
- Adolescence and Puberty
- Changes at Puberty Increase in Height
- Secondary Sexual Characters
- Role of Hormones in Initiating Reproductive Function
- Reproductive Phase of Life in Humans
- How is the Sex of the Baby Determined?
- Hormones other than Sex Hormones
- Role of Hormones in completing the Life History of Insects and Frogs
- Reproductive Health
Important Terms Relevant to understand NCERT Solutions for Class 8 Science Chapter 10 – Reaching the Age of Adolescence :-
Adolescence: The transitional stage when the body undergoes physical, psychological development and reaches reproductive maturity is known as adolescence.
Adam’s apple:An Adam’s apple is the projection in front of the neck due to the extension of the thyroid cartilage of the larynx causing the pitch of the voice to decrease. It is prominent in men.
Secondary sexual characters: The features or the characteristics that allow differentiation between the male and females such as moustache and beard in males and breast enlargement, widening of hip in females are called secondary sexual characters.
Hormones: Hormones are the chemical messengers which allow internal communication between different cells of the body and regulate behaviour.
Endocrine glands: Endocrine glands are the ductless glands that secrete the hormones they produce directly into the bloodstream.
Target site: Target site is the part of the body where any particular hormone secreted by the endocrine gland is supposed to reach and act.
Menstruation: The shedding of the thickened walls of the uterus along with the blood vessels is known as menstruation.
Menarche: The first occurrence of menstruation is referred to as Menarche.
Menopause: Menopause is a condition when a woman stops having periods and is no longer able to get pregnant. It is due to the natural decline in her reproductive hormone.
Sex chromosomes: A pair of chromosomes which are involved in determining the sex of the unborn child are called sex chromosomes.
Goitre: Goitre is a condition which causes inflammation of the neck due to insufficient production of the hormone, thyroxine, by the thyroid gland.
Adrenal glands: Adrenal glands are the endocrine glands present above the kidneys which produce hormones that regulate metabolism, blood pressure, stress regulation and some other vital functions in the body.
Balanced diet: A balanced diet is a diet which includes all the vitamins and the nutrients required by the body in the appropriate amount.
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