Chapter 10 : Reaching the Age of Adolescence

  MULTIPLE CHOICE QUESTIONS

1.The belief that the mother is completely responsible for the sex of the child is wrong because the child
(a) gets sex chromosome only from the mother.
(b) develops in the body of the mother.
(c) gets one sex chromosome from the mother and the other from the father.
(d) gets sex chromosome only from the father.
Answer: (c) gets one sex chromosome from the mother and the other from the father.

[ The child gets one sex chromosome from the mother (X) and one from the father (X or Y), so the father determines the sex.]

2.AIDS can spread from an infected person to another person through
(a) sharing food    (b) blood transfusion     (c) sharing comb  (d) a mosquito bite
Answer: (b) blood transfusion

[ AIDS spreads through infected blood, semen, or breast milk, not through casual contact like sharing food, comb or mosquito bites.]

3.Given below are events that lead to pregnancy and development of embryo.
(i) Fertilization of egg
(ii) Maturation of egg
(iii) Release of egg
(iv) Embedding of embryo in thickened uterine wall.
Which of the following options gives the correct order of sequence in which they occur?
(a) i, ii, iii, iv,        (b) ii, i, iii, iv
(c) i, iv, ii, iii         (d) ii, iii, i, iv.

Answer: (d) ii, iii, i, iv

[ Egg matures first (ii), then releases (iii), then fertilization (i), then embryo embeds in uterus (iv).]

4.For the metamorphosis of tadpoles which of the following elements must be available in water?
(a) chlorine   (b) carbon     (c) sulphur    (d) iodine

Answer:  (d) iodine

[ Iodine is essential for thyroid hormone production, which controls metamorphosis in tadpoles.]

5.The most conspicuous visible change that occurs in boys during puberty is:
(a) development in voice box.     (b) increase in height.

(c) production of sperms.           (d) increased sweating.

Answer: (b) increase in height

[ Rapid increase in height is the most obvious visible change in boys during puberty, easily noticed externally.]

6.Structures present in a cell which is responsible for determination of the sex of a baby is
(a) cytoplasm   (b) cell membrane  (c) nucleus  (d) chromosome  

Answer: (d) chromosome

[ Chromosomes (X and Y) in the nucleus carry genes that determine the sex of a baby.]

VERY SHORT ANSWER QUESTIONS

7. Unscramble the underlined words in the following sentences.
(a) Reproductive life of a woman lasts from hacreemn to spauoemen.
(b) The development of a caterpillar to an adult butterfly is termed as poommertaissh.
(c) The overgrowth of sumselc in xalnyr leads to the hoarse voice in adolescent boys.
(d) Dannalier helps the body to adjust and fight the stress.

Answer: (a) Reproductive life of a woman lasts from menarche to menopause.

(b)  The development of a caterpillar to an adult butterfly is called metamorphosis.

(c) The overgrowth of muscles in the larynx leads to a hoarse voice in adolescent boys.

(d) Adrenaline helps the body to adjust and fight stress.

8.Complete the following sentences.
(a) In females, the uterine wall thickens to receive the __________.
(b) Endocrine glands release hormones directly into___________for transportation to the __________.
(c) The sex hormones,_______________________ and estrogen are responsible for the development of __________ characters.
(d) Release of sex hormones is under the control of a hormone secreted from the __________.

Answer: (a) In females, the uterine wall thickens to receive the embryo.

(b) Endocrine glands release hormones directly into the bloodstream for transportation to the target organs.

(c) The sex hormones, testosterone and estrogen are responsible for the development of secondary sexual characters.

(d) Release of sex hormones is under the control of a hormone secreted from the pituitary gland.

9. Give a suitable word for each of the following statements.
(a) The site which responds to a hormone.
(b) Name of a gland which transports secretions through ducts.
(c) Chemicals which control changes at adolescence stage.
(d) It marks the beginning of reproductive period.

Answer: (a) Target site (or target organ)
(b) Exocrine gland
(c) Hormones
(d) Menarche (in females) / Puberty (general onset)

10. Name the hormone that is released by testes at the onset of puberty.

Answer: The hormone released by the testes at the onset of puberty is testosterone.

11. Name the female hormone produced by ovaries that helps in development of mammary glands.

Answer: The female hormone produced by the ovaries that helps in the development of mammary glands is estrogen.

SHORT ANSWER QUESTIONS

12. Match the hormones given in Column A with their deficiency disease given in Column B.
    Column A                   Column B
(a) thyroxine                   (i) salt imbalance
(b) growth hormone         (ii) diabetes
(c) Insulin                      (iii) goitre
(d) Adrenal hormone       (iv) Dwarfism

Answer: The correct matching is:

(a) thyroxine → (iii) goitre
(b) growth hormone → (iv) Dwarfism
(c) Insulin → (ii) diabetes
(d) Adrenal hormone → (i) salt imbalance

13. Lila always eats only dal and rice in every meal. She often falls ill and has become prone to diseases. Can you suggest changes in her diet which can make her healthy and free from disease?

Answer: Lila should take a balanced diet instead of only dal and rice. She should include green leafy vegetables, fruits, milk, eggs or pulses, and some fats in her meals. This will provide all essential nutrients and improve her immunity, keeping her healthy and disease-free.

14. Mention any two features each that are seen in boys and girls each to distinguish them from each other at puberty.

Answer:  In boys:  (i) Growth of facial hair (moustache, beard). ; (ii) Voice becomes deeper (voice box enlarges).

In girls: (i) Development of breasts.  ;  (ii) Menstruation begins (menarche).

15. We should avoid taking medicines/drugs unless prescribed by a doctor. Give reasons.

Answer: Taking medicines without a doctor’s prescription can cause harmful side effects, addiction and antibiotic resistance. It may also mask symptoms, delay correct treatment or lead to incorrect dosage and serious health complications.

16. A few of Paheli’s classmates eat potato chips and burgers regularly during the recess at school. Are they healthy eating habits? Give reasons.

Answer: No, these are not healthy eating habits. Potato chips and burgers contain excess fat, salt, and refined flour, which can lead to obesity and poor health. They lack essential nutrients like vitamins and minerals. Regular consumption may weaken immunity and reduce energy levels in growing children.

17. Read the statements given below and fill up the blanks with the correct words listed in the box.
                        deep, ductless, nutrients, thyroxine
(a) The meal that includes all __________ is a balanced diet.
(b) Insufficient production of __________ in the tadpoles leads to their incomplete development.
(c) Endocrine glands are also called __________ glands.
(d) After attaining puberty boys develop a__________ voice.

Answer: (a) The meal that includes all nutrients is a balanced diet.

(b) Insufficient production of thyroxine in the tadpoles leads to their incomplete development.

(c) Endocrine glands are also called ductless glands.

(d) After attaining puberty boys develop a deep voice.

18. Fill the blank circles in figure 10.1 and identify the sex of child A and B.

      

Answer:  Child A is girl [ female (XX) ] and Child B is boy [ male (XY) ] .

 

The sex of a child depends on whether the father’s sperm contributes an X or Y chromosome .

LONG ANSWER QUESTIONS

19. During adolescence, the body of boys and girls undergoes certain changes. Given below are a few of those changes.
(a) Broad shoulders
(b) Wider chests
(c) Wider region below waist
(d) Development of muscles
(e) Development of mammary glands
(f) Growth of facial hair
(g) Acne and pimples on face
(h) Development of sex organs
(i) High-pitched voice
(j) Growth of pubic hair.
Categorise these changes into those that occur in boys and those that occur in girls and fill in the table given below.

Body changes during Adolescence
Boys	Girls

Answer:  The correct categorisation of changes during adolescence:

Boys	Girls
Broad shoulders (a)	Wider region below waist (c)
Wider chests (b)	Development of mammary glands (e)
Development of muscles (d)	High-pitched voice (i)
Growth of facial hair (f)	Acne and pimples (g)
Growth of pubic hair (j)	Growth of pubic hair (j)
Development of sex organs (h)	Development of sex organs (h)

20. In Fig.10.2 mark the positions of the endocrine glands which release the hormones that:
(a) controls the release of sex hormones.
(b) is responsible for the secondary sexual characters in boys.
(c) prevents diabetes.
(d) maintains the correct salt balance in the blood.

     

Answer: (a) Pituitary gland
Located at the base of the brain. It controls the release of sex hormones by regulating other endocrine glands.

(b) Testes
Located in the scrotal sacs. They release testosterone, which is responsible for secondary sexual characters in boys.

(c) Pancreas
Located in the upper abdomen. It produces insulin, which helps prevent diabetes by controlling blood sugar levels.

(d) Adrenal glands
Located on top of the kidneys. They maintain the correct salt balance in the blood.

21. Given below are certain food items required for proper nourishment of adolescents. Name the nutrients present in the food items and write their functions.

S. No.	Food items	Major Functions	Function
1.	Pulses and nuts
2.	Oranges and Amla
3.	Sugar, Roti
4.	Oils
5.	Vegetables

Answer:  The completed table is :

S.No.	Food items	Major Nutrients	Function
1.	Pulses and nuts	Protein	Body building, repair of tissues, growth
2.	Oranges and Amla	Vitamin C	Boosts immunity, helps in wound healing, prevents scurvy
3.	Sugar, Roti	Carbohydrates	Provide energy for daily activities
4.	Oils	Fats	Provide energy, keep skin healthy, store fat-soluble vitamins
5.	Vegetables	Vitamins and minerals	Protect against diseases, maintain good health, help body functions

22. Name the hormone which would be released during the following situations:
(a) a frightened person.
(b) growth of a child to adult.
(c) development of caterpillar to moth.
(d) development of tadpole to frog.

Answer: (a) Adrenaline (released during fear or stress)
(b) Growth hormone (from pituitary gland)
(c) Insect hormones (e.g., ecdysone – for metamorphosis in insects)
(d) Thyroxine (essential for metamorphosis in tadpoles)

23. In human females, each time during maturation and release of egg the inner wall of uterus thickens. Is this thickening permanent? Give reasons.

Answer: No, this thickening is not permanent. If fertilization does not occur, the thickened uterine wall breaks down and is shed as blood and mucus during menstruation. The cycle repeats every month

24. John and Radha were classmates since childhood. When Radha became eleven years old, she developed a little swelling on her neck. She visited the doctor who started medication for her. After a few years, John also developed a slight protrusion on his throat. He got worried and went to the doctor. But, the doctor assured him that it was a normal feature in boys while they are growing up. Can you think of any reasons for the difference in diagnoses?

Answer: Radha’s neck swelling was likely a goitre (due to iodine deficiency and low thyroxine), which is abnormal. John’s protrusion was the Adam’s apple (enlarged larynx), a normal secondary sexual change in boys during puberty caused by testosterone.

25. Observe the chart and graph given in Fig. 10.3 carefully and answer the following questions.

Age in years	% of full height
	Boys	Girls
8   9   10   11   12   13   14  15  16  17  18	72%   75%   78%   81%   84%   88%   92%   95%   98%   99%   100%	77%   81%   84%   88%   91%   95%   98%   99%   99.5%   100%   100%

(a) Which of the line represents the height of boys?
(b) Which line represents the height of girls?
(c) What is the difference between the pattern of increase in the height of boys and girls?
(d) Is this pattern true for each individual?

Answer: (a) The line for boys starts at about 72% of their full height at age 8 and gradually reaches 100% by age 18.

(b) The line for girls starts at around 77% at age 8 and reaches 100% by age 17.

(c) Girls grow faster than boys in the beginning. For example, girls reach about 95% of their height by age 14, while boys reach it by around age 15. However, boys continue growing for a longer time (up to 18 years), whereas girls usually stop earlier (by 17 years).

(d) No, this pattern is not the same for every individual. It only shows an average trend, and each person grows at their own pace and timing.

26. Salma had a very soft and smooth skin during her childhood. As she entered adolescence, she developed pimples on her face. The skin specialist advised her to wash her face at regular intervals. Can you explain the reasons for the appearance of pimples on her face and suggest ways to prevent them?

Answer: During adolescence, there is an increase in the activity of sebaceous (oil) glands in the skin due to hormonal changes. These glands start producing excess oil (sebum). Sometimes, the oil and dead skin cells block the pores of the skin. This leads to the growth of bacteria inside the pores, causing swelling and redness, which appear as pimples.

Ways to prevent pimples:

(i) Wash the face regularly with clean water and mild soap to remove excess oil and dirt.

(ii) Avoid touching or squeezing pimples, as it can worsen the infection.

(iii) Keep the skin clean and dry.

(iv) Eat a balanced diet and drink plenty of water.

(v) Maintain proper personal hygiene.

27. Our government has legalised the age for marriage in boys and girls. Give reasons as to why one should get married after a certain age.

Answer: Marriage after legal age (18 for girls, 21 for boys) ensures physical and mental maturity. Early marriage can cause health problems, complications during pregnancy, lack of education and financial instability. Proper age allows couples to raise children responsibly.

28. It is believed that height of a child depends upon the genes inherited from parents. However, it is often seen that tall parents may have short children and vice-versa. Are there factors other than genes, that can cause these variations?

Answer: : Yes, apart from genes, other factors also affect a child’s height. Proper nutrition, health, exercise, and hormones play an important role. Lack of balanced diet or illness during growing years can limit height. So, even if parents are tall, these factors can cause variations in a child’s height.