REACHING THE AGE OF ADOLESCENCE:

Reaching the Age of Adolescence Class 8 Extra Questions Very Short Answer Questions

Question 1.
What is Adam’s apple?
Answer:
The protruding part of the throat in males is called Adam’s apple.

Acne treatment products for adolescents

Question 2.
Name the hormone in female that is produced by ovaries and helps in development of
mammary glands.
Answer:
Estrogen

Question 3.
Whose height grow faster initially—boys or girls?
Answer:
Girls

Question 4.
Name a gland which transports secretions through ducts.
Answer:
Sweat glands/salivary glands/ oil gland (any one).

Question 5.
What is puberty?
Answer:
The age at which boys and girls become capable of reproduction.

Question 6.
What are hormones?
Answer:
The chemical substances produced by endocrine glands are called hormones.

Question 7.
How long is a woman’s reproductive life lasts?
Answer:
Menarche to menopause.

Question 8.
Name the female hormone.
Answer:
Estrogen

Question 9.
Which gland is called master gland?
Answer:
Pituitary gland

Question 10.
What is a balanced diet?
Answer:
The meal that includes all nutrients is called a balanced diet.

Question 11.
What is menstruation?
Answer:
Extrusion of uterus lining and blood along with the unfertilised egg from the vagina is called
menstruation.

Question 12.
What is menarche?
Answer:
The first menstrual flow begins at puberty and is termed as menarche.

Question 13.
What is menopause?
Answer:
Stoppage of menstruation is called menopause.

Question 14.
What causes goitre?
Answer:
Deficiency of thyroxine hormone.

Question 15.
Which gland secretes thyroxine?
Answer:
Thyroid gland

Question 16.
What are chromosomes?
Answer:
The thread-like structures in the nucleus are called chromosomes.

Question 17.
How many chromosomes are present in human cell?
Answer:
23 pairs or 46 chromosomes.

Question 18.
How many sex chromosomes are there in human cell?
Answer:
Two, i.e., one pair.

Question 19.
Which hormone is necessary for normal growth of a person?
Answer:
Growth hormone.

Question 20.
Which gland secretes insulin?
Answer:
Pancreas

Question 21.
What causes diabetes?
Answer:
Deficiency of insulin.

Question 22.
Name the chromosome present in a female.
Answer:
X chromosome

Question 23.
Name the chromosome present in a male.
Answer:
X and Y chromosomes

Question 24.
Which chromosome does the unfertilised egg contain?
Answer:
X chromosome

Question 25.
Which hormone balances the proportion of salts in the blood?
Answer:
Adrenaline

Question 26.
What decides the sex of an unborn child?
Answer:
Sex chromosome of father.

Question 27.
Name the glands other than the pituitary gland.
Answer:
Thyroid, pancreas and adrenals.

Question 28.
When does the puberty ends?
Answer:
uberty ends when an adolescent reaches reproductive maturity.

Question 29.
Do the boys and girls undergo same physical changes at puberty?
Answer:
No

Question 30.
Why do we need to have a balanced diet?
Answer:
To keep the body healthy.

Reaching the Age of Adolescence Class 8 Extra Questions Short Answer Questions

Question 1.
What is meant by adolescence?
Answer:
Growing up is a natural process. The period of life, when the body undergoes several
changes leading to reproductive maturity, is cabled adolescence. The adolescence period is
11 to 19 years of age.

Question 2.
What is puberty?
Answer:
The period during which adolescent boys and girls attain sexual maturity and become
capable of reproduction is called puberty. Puberty age of female is 10 to 12 years while male
puberty age is 12 to 14 years.

Question 3.
What is vital change which marks puberty in boys and girls?
Answer:
During puberty, the human body undergoes several changes, but the most important
changes which marks puberty is that boys and girls become capable of reproduction.
Question 4.
Why do boys have a hoarse voice at puberty?
Answer:
The voice box or larynx begins to grow at the onset of puberty. This growing voice box in
boys can be seen as a protruding part of the throat called Adam’s apple. This leads to voice
becoming hoarse.

Question 5.
How does the body shape change at puberty?
Answer:
Body shape changes differently in boys and girls at puberty. Boys have broader shoulders
and wider chests. Their muscles grow more prominently than girls. In girls, the region below
the waist becomes wider.

Question 6.
Why is adolescence also called teenage?
Answer:
Adolescence period is generally 11 to 19 years of age. Because the period covers the teens,
i.e., 13 to 19 years of age, adolescents are also called teenagers.

Question 7.
Why do many young people have acne and pimples during adolescence?
Answer:
During puberty the secretion of sweat glands and sebaceous glands (oil glands) increases. It
develops acne and pimples on the face of young boys and girls.

Question 8.
Why are endocrine glands also called ductless glands?
Answer:
Endocrine glands release hormones directly into the blood stream. So, they are termed as
ductless glands. For example, pituitary, thyroid, pancreas, etc.

Question 9.
What are secondary sexual characters?
Answer:
At puberty, in girls, breasts begin to develop, the region below the waist become wider,
voice become shriller. Boys begin to grow facial hair, i.e., moustache and beard. Boys also
develop hair on their chest, the muscles of the body grow more prominently, develop larger
voice box which can be seen as a protruding part of the throat called Adam’s apple. In both
boys and girls, hair grows under the arms and in the pubic region. As these features
distinguish the male from the female they are called secondary sexual characters.

Question 10.
Explain the development of sex organs in male and female.
Answer:
The male and the female sex organs develop completely at puberty. Male sex organ like
testes and penis develop completely. The testes begin to produce the male gametes or
sperm. Similarly in girls the ovaries enlarge and egg begins to mature. Ovaries start releasing
matured eggs or ovum.

Question 11.
Why do changes occur in human body at puberty?
Answer:
The changes in human body at puberty occur due to release of hormones by different types
of glands. Hormones are chemical substances secreted from endocrine glands or endocrine
system. Male hormone or testosterone are responsible for changes in male whereas female
hormone or estrogen are responsible for changes in female.

Question 12.
What is a pituitary gland?
Answer:
Different types of hormones are secreted by different types of glands. The product of all
these hormones is under the control of another hormone secreted from an endocrine gland
called pituitary gland.

Question 13.
How do hormones work in human body?
Answer:
Endocrine glands release hormones into the blood stream to reach a particular body part
called target site. The target responds to the hormone. There are many endocrine glands or
ductless glands in the body.

Question 14.
What are sex hormones? How do they work in the human body?
Answer:
Sex hormones help boys and girls develop sex organs to enable them for reproduction.
These hormones lead them to reproductive maturity.

In girls, estrogen makes the breasts develop. Milk secreting glands or mammary glands
develop inside the breasts. Ovaries begin to produce eggs. In boys, testosterone is released
by testes. Testes begin to release sperms. Changes in boys is also seen due to this hormone.

Question 15.
What is menstruation?
Answer:
At puberty, in girls the ovaries get enlarged and start producing eggs (ovum). One egg
matures and is released by one of the ovaries once in about 28 to 30 days. During this
period, the wall of the uterus becomes thick so as to receive the egg. If the egg is fertilised
then it begins to develop and results in pregnancy. If this egg is not fertilised, the released
egg and thickened lining of the uterus along with its blood vessels are shed off causing
bleeding in female which is called menstruation. It occurs once in about 28 to 30 days.

Question 16.
What are the changes in female at the onset of puberty?
Answer:
There are several changes in females at the onset of puberty. They are:

 growth of hair in armpit and pubic region.

 development of breasts and mammary glands.

 ovaries get enlarged and begin producing eggs.

 menstruation cycle starts; and

 increased activity of sweat and sebaceous glands.

Question 17.
Explain the terms menarche and menopause.
Answer:
The first menstrual flow begins at puberty and is termed as menarche.
At 45 to 50 years of age, the menstrual cycle stops. Stoppage of menstruation is called
menopause.

Question 18.
What happens when the egg is fertilised?
Answer:
When the egg is fertilised, it begins to divide and then gets embedded in the uterus for
further development. Finally the fertilised egg develops into a foetus.

Question 19.
What are the changes in males at puberty?
Answer:
There are various changes in males at puberty. They are:

 sudden increase in height.

 growth of hair at different parts of body like face, armpit and pubic region,
development of moustache and beard.

 development of Adam’s apple in throat, voice becomes hoarse.

 shoulders become broader and chest wider.

 growth of size of reproductive organs like penis, testes begin to produce sperms, etc.
Question 20.
What do you mean by reproductive health?
Answer:
The physical and mental well being of an individual is regarded as an individual’s health. To
keep the body healthy, every human being, at any age, needs to have a balanced diet. The
person must also observe personal hygiene and undertake adequate physical exercise.

Thus, reproductive health refers to the diseases, disorders and conditions that affect the
functioning of the male and female reproductive system during all stages of life.

Question 21.
What is the role of hormones in completing the life history of insects and frogs?
Answer:
Hormones play an important role in the completion of life cycle of insects and frogs.
Metamorphosis in insects is controlled by insect hormones. In a frog, it is controlled by
thyroxine, the hormone produced by thyroid gland. Thyroxine production requires the
presence of iodine in water. Water in which iodine is not, present, the tadpoles cannot
become adult.

Question 22.
Which hormone is released by pancreas? What is its function?
Answer:
Insulin is released by pancreatic gland. It regulates sugar metabolism. If insulin is deficient in
the body, sugar level becomes high in blood causing diabetes.

Reaching the Age of Adolescence Class 8 Extra Questions Long Answer Questions

Question 1.
What changes occur in human at puberty?
Answer:
There are various changes in human at puberty. They are as follows:

 Change in height: During puberty, there is sudden increase in height in boys and girls.
Initially, girls grow faster in height than in boys. But both reach their maximum height
at the age of 18 years.

 Change in voice: Boys develop larger voice box or larynx to form protruding part of
throat called Adam’s apple making their voice hoarse, girls have high pitched voice.

 Change in body shape: In boys, shoulders broaden and muscles grow more
prominently than in girls. In girls the region below the waist becomes wider.

 Secretion of sweat and sebaceous glands (oil glands) in both boys and girls increases
and acne or pimples grow on faces of many youths.
  Development of sex organs: In males, testes and penis develop completely. Testes
begin producing sperms. In girls, ovaries are enlarged and begin to produce eggs.
Both boys and girls reach reproductive maturity.

 In girls, menstruation or periods starts.

 All human beings attain mental, intellectual and emotional maturity at puberty.

 Facial hair like moustache and beard are grown in boys. Hair are grown in armpit and
pubic region in both boys and girls. Breasts are developed in girls. These characters
are called secondary sexual characters as they distinguish a male from a female.

Question 2.
Explain the reproductive phase of life in humans.
Answer:
Boys and girls become capable of reproduction at puberty because their testes and ovaries
begin to release gametes, i.e., sperms and ova respectively. In girls, reproductive phase of
life begins at puberty from 10 to 12 years of age and generally lasts till the age of 45 to 50
years. The ova begin to mature with the onset of puberty. The ovum matures and is released
by one of the ovaries once in 28 to 30 days.

During this period, the wall of the uterus becomes thick so as to receive the egg, in case it is
fertilised and begins to develop. This results in pregnancy.
If fertilisation does not occur, the released egg, and the thickened lining of the uterus along
with its blood vessels are shed off. This causes menstruation. It occurs once in about 28 to
30 days. The first menstrual flow begin at puberty and is termed as menarche. The
menstruation stops at the age of 45 to 50. This stage is known as menopause.
In male, the reproductive phase begins at puberty at the ages 14-15 and lasts as long as he is
healthy.

Question 3.
Mention different types of glands, their functions and hormones secreted by them.
Answer:
There are different types of glands in our body and they secrete different types of hormones
which control groftoth, behaviour, development and reproduction. The following table
shows different types of glands, hormones secreted by them and their functions:

Question 4.
Explain sex determination in human.
Answer:

Sex determination of a baby is done at the time of fertilisation when a male gametes fuse
with a female gamete. It depends on male partner whether the baby will be a male child or
female child. The chances of child to be male or female actually depend on the chromsomes
present in the fertilised eggs or ova. There are 23 pairs of chromosomes in the nuclei of all
human beings out of which two are sex chromosomes named X and Y. A male has one X and
one Y chromosome and a female has two X chromosomes. The gametes (egg and sperm)
have only one set of chromosomes. The unfetilised egg always has one X chromosome. But
sperms are of two kinds. One kind has an X chromosome, and the other kind has a Y
chromosome.

When a sperm containing X chromosome fertilises the egg, the zygote would have two X
chromosomes and develop into a female child. If the sperm contributes a Y chromosome to
the egg (ovum) at fertilisation, the zygote would develop into a male child. Fig. 10.5 shows
sex determination in humans.

Question 5.
Explain the term reproductive health. What should we do to maintain reproductive health?
Answer:
The state of physical, mental and social well being of an individual is regarded as an
individual’s health. A healthy person is free from disease, tension and anxiety. Reproductive
health refers to a state of physical, mental and social well-being in all matters relating to the
reproductive system, at all stages of life. We should take following measures to maintain
reproductive health:

 To have a balanced diet: As far as practicable, we should have a balanced diet, i.e., a
diet contain¬
ing proteins, vitamins, carbohydrates, fats and minerals. We can have our food which
contain these nutrients.

 To take physical exercise: We should take physical exercise like morning walk,
running, etc., daily.

 To maintain personal hygiene: We should maintain personal hygiene to stay fit and
healthy. We should wash our body especially pubic region, armpit, etc., properly.

 Avoid harmful drugs: We should avoid taking harmful drugs and alcohol.

Reaching the Age of Adolescence Class 8 Extra Questions Higher Order Thinking Skills

Question 1.
One day Seema’s uncle visited her place. Seema prepared dinner for him. When she was
about to put rock salt on the salad, her uncle interrupted her and asked to put iodised salt
instead of rock salt. He also advised her to prefer iodised salt instead of rock salt. Why do
you think Seema’s uncle advised her to have iodised salt instead of rock salt?
Answer:
Deficiency of iodine causes goitre disease in our body. This is why Seema’s uncle advised her
to have iodised salt.

Question 2.
It is said that height of a child depends upon the genes inherited from the parents. Are there
factors other than genes that causes variation in height?
Answer:
Other factors like nutrition, release of growth hormones, exercises, diseases, etc., also have
impact on the height of a growing child.

Question 3.
Is a woman responsible for the birth of a girl child? Explain.
Answer:
No, because a woman has eggs of only X chromosomes but a male has sperms of both X and
Y chromosomes. It is the type of male chromosome (X or Y) which fuses with the egg and
determine the sex of the foetus, i.e., whether it will be male (XY) or female (XX) child.

Question 4.
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:
The swelling on the neck of Radha may be because of insufficient production of thyroxine
which results in goitre. However slight protrusion in John’s throat may be due to
enlargement of voice box, also known as Adam’s apple, in adolescent boys.

Question 5.
Why we should not take medicines or drugs unless prescribed by a doctor?
Answer:
Certain medicines have specific dosage levels and adverse side effects which if not followed
may be proved lethal to us. Drugs can be addictive too and can ruin our health and
happiness.

Reaching the Age of Adolescence Class 8 Extra Questions Value-Based Questions

Question 1.
Salma had a very soft and smooth skin during her childhood. As she entered adolescence,
she developed pimples on her face, her body became taller compared to her face. She got
worried of all of the sudden changes. Her mother explained that all these changes are
normal and advised her to wash her face at regular intervals.

 Why Salma’s mother advised Salma to wash her face at regular intervals?
  What is the reason for appearance of pimples on her face?

 Why Salma experienced disproportionate growth of the body?

 What values do we get from this?

Answer:

 Regular face wash keeps the face clean and dry and helps to reduce the pimples.

 During adolescence, secretion of sweat glands and sebaceous glands increases

leading to formation of acne and pimples.

 During adolescence, all parts of the body do not grow at the same rate. Sometimes
the arms and legs or hands and feet of adolescents look oversized and out of
proportion with the body.

 We must be self-aware, must take proper care and diet during the growing period,
not get worried or lose our self-esteem.

Activities and Projects

Question 1.
Find out from your elder relatives about their awareness of the legal status of early
marriage. You yourself may get information on it from your teacher, parents, a doctor or the
internet. Write a two minute speech explaining why early marriage is not good for the
couple.
Answer:
Our law does not permit the marriages of girls below 18 years of age and the boys below 21
years.
Biologically also, it is not good for both boys and girls. Early marriages are not good for the
couple due , to following reasons:

 Girls below the age of 18 are not biologically mature enough to produce a baby.

 Boys also are not mature enough to take such a major responsibility to look after
their child properly
and it creates many hurdles in the socio-economic development, education,
maintaining livelihood, etc., of both the boys and girls. .

 The newly born babies also have to suffer many problems regarding their proper
care, etc.

Question 2.
Collect newspaper cuttings and information in magazines about HIV/AIDS. Write a one page
article of 15 to 20 sentences on HIV/AIDS.
Answer:
Introduction: Acquired Immune Deficiency Syndrome (AIDS) is a spectrum of conditions
caused by infection with the human immunodeficiency virus (HIV). It may also be referred to
as HIV disease or HIV infection. Following initial infection, a person may experience a brief
period of influenza-like illqess. This is typically followed by a prolonged period without
symptoms. As the infection progresses, it interferes more and more with the immune
system, making the person much more susceptible to common infections, like tuberculosis,
as well as opportunistic infections and tumors that do not usually affect people who have
working immune systems. The late symptoms of the infection are referred to as AIDS. This
stage is often complicated by an infection of the lung known as pneumocystis pneumonia,
severe weight loss, skin lesions, or other AIDS-defining conditions.

Transmission: HIV is transmitted primarily via unprotected sex, contaminated blood

transfusions,- hypodermic needles, and from mother to child during pregnancy, delivery, or
breastfeeding. Some bodily fluids, such as saliva and tears, do not transmit HIV.

Prevention: Common methods of HIV/AIDS prevention include encouraging and practicing

safe sex, needle-exchange programs, and treating those who are infected. There is no cure
or vaccine; however, antiretroviral treatment can slow the course of the disease and may
lead to a near-normal life expectancy.

Question 3.
In our country, according to 2011 census, there are 940 adolescent females for every 1000
males. Find out
(a) the concerns of the community regarding this low ratio. Remember that the chance of
having a boy or a girl is equal.
(b) what amniocentesis is and how useful this technique is. Why is its use for identification
of sex of the unborn child banned in India?
Answer:
(a) For a long, our society has been male dominated. There is also a belief that only the son
can contin¬ue the lineage and the daughter is other’s property (paraya dhan). This belief
leads to girl foeticide as in most cases, people want a son. This results in low sex ratio.
(b) Amniocentesis is a medical procedure used in prenatal diagnosis of chromosomal
abnormalities, foetal infections and sex determination. For this a small amount of amniotic
fluid, which contains foetal tissues, is sampled from the amniotic sac surrounding a
developing foetus using a needle.
In India, selective abortion of female foetuses due to preference of male child has enforced
Indian Government to ban sex-determination through amniocentesis.

Question 4.
Put your ideas together and write a short note on the importance of knowing facts about
reproduction.
Answer:
Sex education or knowing facts about reproduction is very important due to the following
reasons:
  To know about the proper age of reproduction.

 To become aware of safe sex, health and hygiene.

 To maintain proper gap between two children because we come to know about
different methods of family planning.

 To be aware of myths, superstition, do’s or don’t.

I.Multiple Choice Questions (MCQs)

Choose the correct option.
Question 1.
The adolescence period is
(a) 14 – 20 years
(b) 10 – 18 years
(c) 11 – 19 years
(d) none of these

Question 2.
Larynx is called
(a) music box
(b) voice box
(c) respiratory organ
(d) sound box

Question 3.
Most adolescents attain their maximum height around the age of
(a) 22 – 25 years
(b) 13-15 years
(c) 11 – 12 years
(d) 18 – 19 years

Question 4.
Initially girls grow
(a) slower than boys
(b) faster than boys
(c) both of these
(d) none of these

Question 5.
Puberty age in females is
(a) 10 – 12 years
(b) 12 – 14 years
(c) 8-10 years
(d) 5-6 years
Question 6.
Puberty age in males is
(a) 12 – 14 years
(b) 13 – 15 years
(c) 10 – 12 years
(d) 18 -20 years

Question 7.
Thyroxine hormone is produced by
(a) adrenal gland
(b) testes
(c) pituitary gland
(d) thyroid gland

Question 8.
The male hormone is called
(a) estrogen
(b) testosterone
(c) thyroxine
(d) insulin

Question 9.
The female hormone is called
(a) estrogen
(b) testosterone
(c) adrenaline
(d) none of these

Question 10.
Menstruation occurs once in about
(a) 28 to 30 days
(b) 25 to 30 days
(c) 45 to 50 days
(d) none of these

Question 11.
The number of chromosomes present in human cell are
(a) 25 pairs
(b) 22 pairs
(c) 23 pairs
(d) none of these

Question 12.
The number of sex chromosomes are
(a) three
(b) two
(c) four
(d) none of these

Question 13.
The age of menopause stage is
(a) 45 to 50 years
(b) 40 to 45 years
(c) 50 to 55 years
(d) none of these

Question 14.
The unfertilised egg always has __________ chromosome
(a) X
(b) Y
(c) XY
(d) XX

Question 15.
A female has
(a) XY chromosomes
(b) YY chromosomes
(c) XX chromosomes
(d) none of these

Question 16.
The gametes have only
(a) one set of chromosomes
(b) two sets of chromosomes
(c) three sets of chromosomes
(d) none of these

Question 17.
Which of the following is male gonads?
(a) Moustache
(b) Chest
(c) Testes
(d) Hair

Question 18.
Production of thyroxine requires
(a) magnesium
(b) iodine
(c) sodium
(d) bromine

Question 19.
Which of the following determines the sex of the baby?
(a) Chromosomes
(b) Chloroplast
(c) Hormones
(d) Pituitary gland

Question 20.
Pancreas is responsible for maintaining
(a) blood pressure
(b) fat metabolism
(c) blood glucose level
(d) electrolyte balance
Answer:
1. (c)
2. (b)
3. (d)
4. (b)
5. (a)
6. (a)
7. (d)
8. (b)
9. (a)
10. (a)
11. (c)
12. (b)
13. (a)
14. (a)
15. (c)
16. (a)
17. (c)
18. (b)
19. (a)
20. (c)

II. Fill in the Blanks

Fill in the blanks with suitable word/s.
1. ___________ means to grow into maturity.
2. Children gain height during ___________.
3. The boys and girls passing through the adolescence period are called ___________ or
___________.
4. During puberty, a change in voice takes place due to the increase in the size of
___________ or ___________.
5. The stage when the menstrual cycle stops is called ___________.
6. The ___________ gland helps in controlling the production of both testosterone and
estrogen hormones.
7. Diabetes is caused due to the deficiency of ___________ in the body.
8. ___________ is caused due to deficiency of thyroxine hormone.
9. Endocrine glands are also called ___________ glands.
10. ___________ secrets male sex hormones.
11. ___________ secrets female sex hormones.
12. Sex of the unborn child depends on whether the ___________ has ___________ or
___________ chromosomes.
13. Metamorphosis in insects is controlled by ___________ hormone.
14. Metamorphosis in frog is controlled by ___________ hormone.
15. If the water in which tadpoles are growing does not contain sufficient ___________, the
tadpoles cannot become adults.
16. In females, the uterine wall thickens to receive the ___________.
17. Endocrine glands release hormones directly into the ___________ for transportation to
the ___________.
18. ___________ helps the body to adjust and fight the stress.
19. The development of a caterpillar to an adult butterfly is termed as ___________.
20. The first menstrual flow begins at ___________ and is termed as ___________.
Answer:
1. Adolescence
2. puberty
3. adolescents, teenagers
4. voice box, larynx
5. menopause
6. pituitary
7. insulin
8. Goitre
9. ductless
10. Testes
11. Ovary
12. zygote, XX, XY
13. insect
14. thyroxine
15. iodine
16. zygote
17. blood stream, target site
18. Adrenaline
19. metamorphosis
20. puberty, menarche 18. Adrenaline

III. Match the following

Match the items given in column I suitably with those given in column II.

Answer:
1. (j)
2. (i)
3. (f)
4. (e)
5. (b)
6. (c)
7. (h)
8. (d)
9. (g)
10. (a)

IV, True or False

State whether the given statements are true or false.
1. The age of adolescence is 15 to 20 years.
2. The female puberty starts at the age of 12 to 14 years.
3. Boys have enlarged and well developed Adam’s apple.
4. Insulin is secreted by pituitary gland.
5. The chemical substances secreted by endocrine glands are called hormones.
6. . Estrogen is female hormone.
7. Testosterone is male hormone.
8. There are 23 pairs of chromosomes in the nuclei of human cell.
9. Menstruation stops in men permanently around the age of 45 to 50 years.
10. The estrogen hormone develops deeper voice in males at puberty.
11. The sex of an unborn child is determined after a foetus is formed.
12. Initially girls grow faster than boys.
13. Thyroxine hormone is released by thyroid gland.
14. Diabetes is caused due to the deficiency of adrenaline hormone.
15. Menstrual cycle in women is controlled by enzyme.
16. Growth hormones are secreted by pituitary glands.
17. Metamorphosis in insects are controlled by growth hormone.
18. Menstruation occurs once in about 28 to 30 days.
19. There are 3 sex chromosomes present in the nuclei of human being.
20. A male has two X chromosomes.o
21. The gametes have only one set of chromosomes.
22. The unfertilised egg has two X chromosomes.
23. At puberty, the voice box or the larynx begins to grow.
24. When the zygote has one X and one Y chromosome, a male child is developed.
25. Menopause is the stage when menstruation starts.
Answer:
1. False
2. False
3. True
4. False
5. True
6. True
7. True
8. True
9. False
10. False
11. False
12. True
13. True
14. False
15. False
16. True
17. False
18. True
19. False
20. False
21. True
22. False
23. True
24. True
25. False

Question 1: Name the hormone that regulates secondary sexual characters in males.

Answer: Testosterone

Question 2: Name the hormone that regulates secondary sexual characters in females.

Answer: Estrogen

Question 3: Which virus causes AIDS?

Answer: AIDS is caused by a dangerous virus, HIV.

Question 4: Which of the two, sperm or egg cell (ovum), decides the sex of the child?

Answer: Sperm decides the sex of the child.

Question 5: What is goitre?

Answer: A goiter is an abnormal enlargement of thyroid gland.

Question 6: Which hormone deficiency in the body causes diabetes?

Answer: Deficiency of insulin hormone in the body causes diabetes.

Question 7: How do shoulders and chest change in boys during puberty?

Answer: Boys develop broader shoulders and wider chests during puberty.

Question 8: What is the other name of voice box?

Answer: The larynx is another name for the voice box.

Question 9: Name some endocrine glands.

Answer: Pituitary, Testes, Ovaries, Thyroid, Pancreas and Adrenals

Question 10: What is the natural balanced food for infants?

Answer: For infants, mother’s milk provides all the nourishment that they need.

Question 11: Name the female sex hormone.

Answer: Estrogen is the female sex hormone released by ovaries.

Question 12: Name the male sex hormone.

Answer: Testosterone is the male sex hormone released by the testes.

Question 13: What gland controls sex hormones?

Answer: Pituitary gland controls sex hormones.

Question 14: Name the endocrine gland attached to the brain.

Answer: Pituitary gland is an endocrine gland attached to the brain.

Question 15: Which endocrine gland secretes growth hormone?

Answer: Pituitary gland secretes growth hormone.

Question 16: What element is needed for thyroxine production?

Answer: Thyroxine production requires the presence of iodine.

Question 17: State the main symptom of goitre.

Answer: Main symptom of goitre include very big and bulging throat.

Question :18 Which hormone deficiency in the body causes goitre?

Answer: Goitre is caused by deficiency of thyroxine hormone in the body.

Question 19: Which gland secretes insulin hormone?

Answer: Pancreas secretes insulin hormone.

Question 20: Who attains puberty at an earlier age in human beings: boys or girls?

Answer: In girls, adolescence may begin a year or two earlier than in boys.

Question 21: What is the most conspicuous change during puberty?

Answer: The most conspicuous change during puberty is the sudden increase in height.

Question 22: State the age at which adolescence usually begins and the age up to which it
lasts.
Or
At what age adolescence usually begins and up to which it lasts?

Answer: Adolescence begins around the age of 11 and lasts up to 18 or 19 years of age.

Question 23: Which disease is caused by the insufficient production of insulin hormone by
pancreas?

Answer: Diabetes is caused by the insufficient production of insulin hormone by pancreas.

Question 24: Which endocrine gland secretes hormone that maintains correct salt balance
in the blood?

Answer: Adrenal glands secrete hormones which maintain the correct salt balance in the
blood.

Short Answer Type Questions

Question 1: What is the legal age for marriage of boys and girls in our country?

Answer: In our country, the legal age for marriage is 18 years for girls and 21 years for boys.

Question 2: How do hips of girls change during puberty?

Answer: Girls develop broader hips during puberty. Due to this, region below the waist
becomes wider.

Question 3: Why endocrine glands are called ductless glands?

Answer: Endocrine glands release hormones directly into the bloodstream. So, they are also
termed ductless glands.

Question 4: Which hormone is responsible for metamorphosis in frog?

Answer: In a frog, metamorphosis is controlled by thyroxine, the hormone produced by

thyroid.

Question 5: Which two male sex organs develop completely at puberty?

Answer: At puberty, male sex organs like the testes and penis develop completely. The testes
also begin to produce sperms.

Question 6: Which two female sex organs develop completely at puberty?

Answer: In girls, the ovaries enlarge and eggs begin Also ovaries start releasing mature
eggs.to mature.

Question 7: What is puberty?

Answer: The period during which adolescent boys and girls reach sexual maturity and
become capable of reproduction is called puberty.

Question 8: What are hormones? Where are hormones made in the human body?

Answer: Hormones are chemical substances. These are secretions from endocrine glands, or
endocrine system.

Question 9: What is the function of adrenalin hormone in the body?

Answer: Adrenals also produce the hormone adrenalin. It helps the body to adjust to stress
when one is very angry, embarrassed or worried.

Question 10: Name the time period in one’s life when the brain has the greatest capacity for
learning.

Answer: Adolescence is often the time in one’s life when the brain has the greatest capacity
for learning.

Question 11: Why is exercise important during adolescence?

Answer: Walking and playing in fresh air keeps the body fit and healthy. Thus, all young boys
and girls should take walks, exercise and play outdoor games.

Question 12: What is the effect of a smaller voice box in grown up girls?

Answer: In girls, the larynx is hardly visible from the outside because of its small size. The
smaller voice box in girls gives shrill voice or high pitched voice to the girls.

Question 13: Why is iron mineral important for our body? Write some iron rich foods.

Answer: Iron mineral is important for our body because it builds blood. Iron-rich food
includes leafy vegetables, jaggery, meat, citrus, Indian gooseberry (amla) etc.

Question 14: When adolescent girls should take special care of personal hygiene?

Answer: Girls should take special care of cleanliness during the time of menstrual flow. They
should keep track of their menstrual cycle and be prepared for the onset of menstruation.

Question 15: Why drugs should be avoided?

Answer: Drugs should be avoided because they are addictive. If we take them once, we

feel like taking them again and again. They harm the body in the long run. They ruin health
and happiness.

Question 16: What is the effect of a larger voice box in grown up boys?

Answer: The bigger voice box in boys gives deeper voice or low pitched voice to the boys. In
adolescent boys, sometimes, the muscles of the growing voice box go out of control and the
voice becomes hoarse.

Question 17: What is menarche and menopause?

Answer: Menstruation occurs once in about 28 to 30 days. The first menstrual flow begins at
puberty and is termed menarche. At 45 to 50 years of age, the menstrual cycle stops.
Stoppage of menstruation is termed menopause.

Question 18: Why do young people get acne?

Answer: During puberty the secretion of sweat glands and sebaceous glands (oil glands)
increases. Many young people get acne and pimples on the face at this time because of the
increased activity of these glands in the skin.

Question 19: What is the term used for secretions of endocrine glands responsible for
changes taking place in the body?

Answer: Hormones are chemical substances. These are secretions from endocrine glands, or
endocrine system. They are responsible for changes taking place in the body.

Question 20: Why is good hygiene important during adolescence?

Or
Why is it necessary for adolescents to take bath regularly?
Or
What will happen if personal hygiene is not maintained by adolescent?

Answer: It is necessary for teenagers because the increased activity of sweat glands
sometimes makes the body smelly. All parts of the body should be washed and cleaned
every day. If cleanliness is not maintained there are chances of catching bacterial infection.

Question 21: Why early marriage and motherhood is harmful to the girls?

Answer: Early marriage and motherhood cause health problems in the mother and the child.
It also curtails employment opportunities for the young woman and may cause mental
agony as she is not ready for responsibilities of motherhood.

Question 22: What will happen if the water in which tadpoles are growing does not contain
iodine?

Answer: In a frog, metamorphosis is controlled by thyroxine, the hormone produced by

thyroid. Thyroxine production requires the presence of iodine in water. If the water in which
the tadpoles are growing does not contain sufficient iodine, the tadpoles cannot become
adults.

Long Answer Type Questions

Question 1: Define adolescence.

Answer: The period of life, when the body undergoes changes, leading to reproductive
maturity, is called adolescence. Adolescence begins around the age of 11 and lasts upto 18
or 19 years of age. In girls, adolescence may begin a year or two earlier than in boys. Also,
the period of adolescence varies from person to person.

Question 2: How AIDS spread?

Or
What are the various ways in which AIDS virus HIV can be transmitted?
Or
Explain how the use of drugs helps in spreading AIDS disease.

Answer: AIDS which is caused by a dangerous virus, HIV. This virus can pass on to a normal
person from an infected person by sharing the syringes used for injecting drugs. It can also
be transmitted to an infant from the infected mother through her milk. The virus can also be
transmitted through sexual contact with a person infected with HIV.

Question 3: On what factors height depends?

Or
What determines the height of a person?
Answer: Height of an individual is more or less similar to that of some family member. This is
because height depends on the genes inherited from parents. It is, however, very important
to eat the right kind of food during these growing years. This helps the bones, muscles and
other parts of the body get adequate nourishment for growth.

Question 4: How does the height of boys and girls change during puberty?

Answer: At the time of puberty the long bones, that is, the bones of the arms and the legs
elongate and make a person tall. Initially, girls grow faster than boys but by about 18 years of
age, both reach their maximum height. The rate of growth in height varies in different
individuals. Some may grow suddenly at puberty and then slow down, while others may
grow gradually.

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

Answer:

Endocrine glands Hormones

Thyroid gland thyroxine

Pancreas insulin

Pituitary growth hormone

Adrenals adrenalin

Testes testosterone

Ovaries estrogen

Question 6: What is menstruation? Explain.

Answer: In females, the reproductive phase of life begins at puberty (10 to 12 years of age)
and generally lasts till the age of approximately 45 to 50 years. The ova begin to mature with
the onset of puberty. One ovum matures and is released by one of the ovaries once in about
28 to 30 days. During this period, the wall of the uterus becomes thick so as to receive the
egg, in case it is fertilised and begins to develop. This results in pregnancy. If fertilisation
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.

Question 7: What are sex hormones? Why are they named so? State their function.
Answer: Sex hormones are chemical substances produced by a sex gland or other organ. For
example, the testes make male sex hormone called testosterone and the ovaries make
female sex hormone called estrogen. These hormones affect the sexual features of an
organism. Hence they are called sex hormones.

Functions

Testosterone – It produces male secondary sexual characteristics in boys such as deeper

voice, growth of moustache and beard, broad shoulders and chest, adam’s apple, more
muscles, development of reproductive organs etc.

Estrogen – It produces female secondary sexual characteristics in girls such as development

of breasts, broader hips, development of reproductive organs etc.

Question 8: List changes in the body that take place at puberty.

Or
State some of the changes which take place in boys and girls during adolescence.

Answer: Changes at puberty

 Sudden increase in height and weight.

 Boys develop broader shoulders and wider chests. In girls, the region below the waist
becomes wider.

 In boys, the muscles of the body grow more prominently than in the girls.

 Boys develop larger voice boxes. The growing voice box in boys can be seen as a
protruding part of the throat called Adam’s apple.

 Development of pimples and acne on the face due to the increased activity of
sebaceous glands and sweat glands present in the skin.

 At puberty, male sex organs like the testes and penis develop completely. The testes
also begin to produce sperms. In girls, the ovaries enlarge and eggs begin to mature.

 In girls, breasts begin to develop at puberty and boys begin to grow facial hair, that is,
moustaches and beard.

 Boys also develop hair on their chest. In both, boys and girls, hair grows under the
arms and in the region above the thighs or the pubic region.

Question 9: Write notes on—

(a) Adam’s apple.
(b) Secondary sexual characters.
(c) Sex determination in the unborn baby.
Answer: (a) Adam’s apple – At puberty, the voice box or the larynx begins to grow. Boys
develop larger voice boxes. The growing voice box in boys can be seen as a protruding part
of the throat called Adam’s apple.

(b) Secondary sexual characters – In girls, breasts begin to develop at puberty and boys
begin to grow facial hair, that is, moustaches and beard. As these features help to distinguish
the male from the female they are called secondary sexual characters. Boys also develop
hair on their chest. In both, boys and girls, hair grows under the arms and in the region
above the thighs or the pubic region.

(c) Sex determination in the unborn baby – All human beings have 23 pairs of chromosomes
in the nuclei of their cells. Two chromosomes out of these are the sex chromosomes, named
X and Y. 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. But sperms are of two kinds. One kind has an X
chromosome, and the other kind has a Y chromosome. When a sperm containing X
chromosome fertilises the egg, the zygote would have two X chromosomes and develop into
a female child. If the sperm contributes a Y chromosome to the egg (ovum) at fertilisation,
the zygote would develop into a male child.

ery Short Answer Questions: 1 Marks

1. The period of maturity of reproductive organs is called ___________.

A. adolescence period B. menstruation

C. gestation period D. none of these

Ans: A. adolescence period

2. Puberty age in females is __________.

A. 10-12 B. 12-14

C. 8-10 D. more than 14 years

Ans: A. 10-12

3. 3. There are _____ pairs of chromosomes in human cells.

A. 23 B. 46 C. 22 D. 44

Ans: A. 23

4. Bleeding in women in about 28 to 30 days is called the ___________ phase.

A. menarche B. menopause
C. menstruation D. bleeding

Ans: C. menstruation

5. The physical and mental well-being of an individual is called an individual’s ___.

A. health B. disorder

C. growth D. nurturing

Ans: A. health

6. Egg is a ________.

A. egg gamete B. female gamete

C. male gamete D. diploid cell

Ans: B. female gamete

7. Initially, girls grow _____ than boys.

A. faster B. slower

C. at same pace D. none of these

Ans: A. faster

8. Adolescents should be totally away from _______.

A. cold drinks B. fast food

C. drugs D. sweets

Ans: C. drugs

9. Which one of the following regulates the growth of an individual?

A. insulin B. growth hormone

C. adrenalin D. testosterone

Ans: B. growth hormones.

10. Define puberty.

Ans: The process by which a child's body evolves into an adult body and achieves sexual
maturity is known as puberty. With most children it occurs generally around 10-12 years of
age.

11. What is Adam's apple?

Ans: At puberty, a bigger voice box develops in boys, which can be seen as a projecting
region of the throat. This is referred to as Adam's apple.
12. Define hormones.

Ans: Hormones are chemical substances produced by the endocrine glands.

13. Define adolescence.

Ans: Adolescence is the stage of life when the body experiences changes that lead to
reproductive maturity. Adolescence begins around the age of eleven and lasts until the age
of eighteen or nineteen.

14. What are secondary sexual characters?

Ans: Secondary sexual traits are characteristics that help distinguish a man from a woman.
For example, boy’s moustaches and beards, and development of breasts in females.

15. Which hormones help in the development of secondary sexual characters?

Ans: In males and females, testosterone and estrogens respectively aid in the development
of secondary sexual characteristics.

Short Answer Questions: 3 Marks

16. What is pituitary gland? Name the hormones secreted by it?

Ans: The pituitary gland is an endocrine gland that regulates the activity of all other glands
in the body. Some of the hormones secreted by pituitary gland are as follows:

a. Growth Hormones

b. Prolactin

c. Thyroid-stimulating hormone, etc.

d.

e.

17. What do you mean by target site?

Ans: Endocrine glands secrete hormones into the bloodstream in order for them to reach a
specific body part known as a target site. Target sites respond to hormones in various ways.

18. Write a short note on the reproduction phase in humans.

Ans: When adolescent’s testes and ovaries begin to create gametes in males and females
respectively, they are able to reproduce. Males have a substantially longer capability for
maturation and the creation of gametes than females. The reproductive period of females
begins in puberty at the age of 10 to 12 years and lasts until about 45 to 50 years of age.
The reproductive phase of males begins in puberty at the age of 11 to 13 years and lasts a
lifetime.

19. What do you mean by:

a. Menstruation: Normal vaginal bleeding that happens as part of a woman's monthly cycle
is known as menstruation, or period. Your body prepares for pregnancy every month. The
uterus or womb removes its lining if no pregnancy develops. Menstrual blood is a mixture of
blood and tissue from the uterus.

b. Menarche: The first menstrual cycle in a female adolescent is known as menarche.

c. Menopause: Menopause is the term used to describe the end of a woman's menstrual
cycle. Menopause could hit in the forties or fifties.

20. Complete the Following Table:

Hormones Gland Uses

Thyroxin thyroid Overall metabolic rate of the body

insulin Pancreas Controls blood sugar levels

Adrenalin adrenal Prepares the body for fight or flight

Ans:

Hormones Gland Uses

Thyroxin Thyroid Control overall metabolic rate of the body

Pancrea
Insulin Controls blood sugar level
s

Adrenalin Adrenal Prepares the body for fight or flight

21. What are sex chromosomes?

Ans: A sex hormone is a chemical substance produced by a sex gland or other organ that
affects an organism's sexual characteristics. In the nucleus of all human cells, there are 23
pairs of chromosomes. The sex chromosomes, X and Y, are two of these chromosomes.
Males have one X and one Y chromosome, while females have two X chromosomes.

22. Why are drugs harmful for the human body?

Ans: The effects of drugs can differ from one person to the next. Drugs can have both short
and long-term consequences. Physical and psychological problems, as well as dependency,
can occur. The more you use a drug, the more likely it is that you may develop a tolerance to
its side effects. The central nervous system of your body is affected by drugs. They have an
impact on how you think, feel, and act. Three major types of drugs are as follows:
 a. Depressant

b. Stimulant

c. Hallucinogens

d.

e.

23. Write a short note on AIDS.

Ans: The human immunodeficiency virus (HIV) causes acquired immunodeficiency syndrome
(AIDS), a chronic, potentially fatal disease (HIV). HIV is a sexually transmitted illness that
affects both men and women (STI). It can also be passed from mother to child during
pregnancy, childbirth, or breast-feeding and by contact with infected blood. Although there
is no cure for HIV/AIDS, drugs can significantly decrease the disease's course. AIDS weakens
our immune system drastically. The following are few known symptoms of AIDS:

a. Fever

b. Headache

c. Muscles Ache and Joint Pains

d. Rashes

e. Weight Loss, etc.

f.

g.

Long Answer Questions: 5 marks

24. Differentiate between changes occurring in males and females at puberty.

Ans:

Changes in Boys Changes in Girls

Development of testosterone Beginning of menstrual cycle.

Broadening of shoulder Body becomes curvier.

Wider chest Development of mammary gland

Development of adam’s apple High pitched voice

Growth of facial hairs Development of acne.

25. How is sex of a child determined?

Ans: In the nucleus of all human cells, there are 23 pairs of chromosomes.

The sex chromosomes, X and Y, are two of these chromosomes. There is just one set of
chromosomes in the gametes (egg and sperm). One X chromosome is always present in an
unfertilized egg. However, there are two types of sperm. The X chromosome is found in one
type, whereas the Y chromosome is found in the other. During fertilisation, if the X
chromosome of the female egg combines with the X chromosome of male, it develops into a
female child and if X chromosome of the female egg combines with Y chromosome of male,
it develops into a male child.

26. Why should adolescents have a balanced diet?

Ans: Adolescence is a period of rapid development and growth. Regular healthy diet is
required to achieve optimum physical, mental, emotional, and psychological wellness. As a
result, an adolescent's nutrition must be carefully planned. A balanced diet is one in which
the proteins, carbohydrates, fats, and vitamins are all present in the proper quantities.

Multiple Choice Questions

Question. 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) The child gets one sex chrbmosome from the mother and one from the father.
The mother has XX combination and always contributes an X-chromosome.
It is the sperm of father which determines the sex of the child. This is because half of the
sperms have X-chromosome and ofher half have Y-chromosome.

Question. 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) AIDS causing virus can be easily passed from an infected person to another
person through: – ’
1. Sharing of syringes for blood transfusion, taking drugs, etc.
2. Sexual contact
3. From infected mother to foetus
It is not spread through an insect vector (such as insect bite) or through casual contact (such
as sharing food, comb, etc).

Question. 3 Given below are events that lead to pregnancy and development of embryo.
(i) Fertilisation of egg
(ii) Maturation of egg
(iii) Release of egg
(iv) Embedding of embryo in uterus
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) The events in sequence are:
– Maturation of egg after puberty in the ovaries of a woman.
– Release of egg call.
– Fertilisation of egg cell by sperm to form a zygote.
– Zygote divides repeatedly to form an embryo.
– Embryo is embedded in wall of uterus for further development to foetus.

Question. 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) For metamorphosis of tadpoles, iodine should be present in water. This is
because metamorphosis is brought about by thyroxine hormone that requires the presence
of iodine for its production by thyroid gland.

Question. 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) The most visible change during puberty in boys is sudden increase in height. At
this time, the long bones elongate and make a person tall.

Question. 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) The sex of a baby is determined by the type of sex chromosomes present in the
fertilised egg from which the baby develops. There are two types of sex chromosomes-X and
Y.
A female has only two X-chromosomes, i.e. XX, whereas a male has one X and one Y-
chromosome, i.e. XY combination.
Very Short Answer Type Questions

Question. 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 xalnvr leads to the hoarse voice in adolescent boys.
(d) Dannalier helps the body to adjust and fight the stress.
Answer. (a) menarche, menopause (b) metamorphosis
(c) muscles, larynx (d) adrenaline

Question. 8 Complete the following sentences.

(i) In females, the uterine wall thickens to receive the
(ii) Endocrine glands release hormones directly into for transportation to the

(iii) The sex hormones, and oestrogen are responsible for the development of characters.
(iv) Release of sex hormones is under the control of a hormone secreted from the
Answer. (i) fertilised egg (ii) blood stream; target site/organ
(iii) testosterone (iv) pituitary gland

Question. 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 (b) Sweat gland/salivary gland
(c) Hormones (d) Puberty

Question. 10 Name the hormone that is released by testes at the onset of puberty.
Answer. Testosterone is the male hormone, which is released from the testes at the onset of
puberty in males. It produces the male secondary sexual characteristics and causes the
growth and development of male sex organs.

Question. 11 Name the female hormone produced by ovaries that helps in development of
mammary glands.
Answer. Oestrogen Is the female hormone produced by ovaries that help in development of
breasts/mammary glands. It also produces female secondary sexual characteristics and
causes the growth and development of female sex organs.
Short Answer Type Questions

Question. 12 Match the hormones given in Column I with their deficiency disease given in
Column II.
Answer. The correct matching]? as.given:
(a)—(iii), (b)—(iv), (c)—(ii). (d)—(i)

Question. 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’s diet is not a balanced diet because her meal does not contain the adequate
nutritional requirement. She takes only proteins and carbohydrates in every meal. She also
requires vitamins and minerals in her meal to protect from various diseases.
Thus, I would suggest her to include fruits and vegetables in her meal, to obtain vitamins
and minerals and complete her diet.

Question. 14. Mention any two features of each that are seen in boys and girls which
distinguish them from %ach other at puberty.
Answer. Two features seen in boys at puberty are:
(i) Growth of facial hairs (moustache and beard).
(ii) Voice becomes hoarse (Adam’s apple seen as bulge).
Two features seen in girls at puberty are:
(i) Development of breasts.
(ii) Region below the waist becomes wider (broader hips).

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

Ans. We should avoid taking medicines/drugs unless prescribed by a doctor because:
(i) Several medicines have adverse side effects and have specific dosage levels which if
not followed may harm the body.
(ii) Drugs can be addictive too and can ruin our health and happiness.

Q. 16 A few of Paheli’s classmates eat potato chips and- burgers regularly during the recess
in school. Are these healthy eating habits? Give reasons.
Ans. No, these are not healthy eating habits because burgers and potato chips’have very
little nutritional value. Although, these are very tasty but can never replace regular meals
that forms balanced diet and is essential for the adolescents for their normal growth and
development.

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

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

Answer. The circle in the figure can be completed as:

A is a girl. The ovum carrying X-chromosome has been fertilised by a sperm carrying X-
chromosome, resulting a zygote with XX combination of sex chromosomes. So, the child
born will be a female.
8 is a boy. In this case, the X-chromosome carrying ovum has been fertilised by a sperm
carrying Y-chromosome. This results in formation of zygote with XY combination of sex
chromosomes. So, the child born will be a male.

Long Answer Type Questions

Question. 19 During adolescence, the body of boys and girls undergoes certain changes.
Given below are 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 .

Answer. Body changes during adolescence are given below in the table:

Question. 20 In figure, mark the positions of the endocrine glands which release the
hormones that
(a) control the release of sex hormones.
(b) are responsible for the secondary sexual characters in boys.
(c) prevent diabetes.
(d) maintain the correct salt balance in the blood.
Answer. The figure with positions of the endocrine glands marked is given below:

(a) Pituitary gland It releases hormones that control the release of sex hormones, i.e.
testosterone in males and oestrogen in females.
(b) Testis It releases testosterone, which is responsible for the secondary sexual characters in
boys.
(c) Pancreas It releases insulin which prevents diabetes.
(d) Adrenal gland It releases aldosterone that maintains the correct salt balance in the
blood.

Question. 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.
Answer. The food items, major nutrients and their functions are tabulated below:

Question. 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 is secreted from adrenal gland during the stress conditions like fright
or fear, anger, worry or embarrassment. The hormone prepares the body to function at
maximum efficiency by increasing the heart beat and breathing rate, raising B.R, etc.
(b) Growth hormone is secreted from pituitary gland to regulate the normal growth of a
person, i.e. growth of a child to adult. Its deficiency in childhood makes a person dwarf,
while its excess makes a person very tall (gigantism).
(c) Insect hormones control the development of caterpillar to moth, i.e. ‘ metamorphosis.
(d) Thyroxine is produced by thyroid gland to control the development of tadpole to frog.
Iodine in water is necessary for its production.

Question. 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 of the uterine wall is not permanent.
If the egg gets fertilised, it begins to divide to form an embryo. The embryo gets embedded
in the uterine wall resulting in pregnancy. During pregnancy, no more eggs are released and
the thickened lining is discharged only when the baby is born.
However, if fertilisation does not occur, the released egg and the thickened lining of uterus
along with blood vessels are shed off that resulting in menstruation.

Question. 24 John and Radha were classmates since childhood. When Radha became eleven
years old, she developed a little swelling in 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. The swelling on the neck of Radha may have been because of goitre, a condition
during which the thyroid gland produces insufficient quantity of thyroxine. However, the
protrusion in John’s throat would be due to Adam’s apple (bulge) that is a result of growth of
voice box in adolescent boys.

Question. 25 Observe the chart and graph given’in figure carefully and answer the
following questions.

(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 dotted line represents the height of boys.
(b) The solid line represents the height of girls.
(c) At the omset of puberty, girls grow faster in height than the boys and by the age of 18
years, approximately both reach their maximum height.
(d) No, the rate of growth in height varies among individuals. Some may grow in height
suddenly at puberty and then slow down, while others may grow gradually.

Question. 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, the secretion of sweat glands (sweat) and sebaceous glands
(oil) increases. The excess oil and sweat gets collected in the tiny pores of the skin blocking
them.
Bacteria grow in these blocked pores causing swelling and redness which leads to the
formation of acne and pimples. Regular face wash keeps the face clean and dry and helps to
reduce the pimples.

Question. 27 Our government has legalised the age for marriage in boys and girls. Give
reasons asTt) why one should get married after a certain age?
Answer. In our country, the legal age for marriage is 18 years for girls and 21 years for boys.
This is because teenage mothers are not prepared mentally or physically for motherhood.
Early marriage and motherhood causes health problems in both mother and the child.
It also curtails employment opportunities for the young woman and may cause mental
agony as she is not ready to shoulder responsibilities of motherhood.
Also, the boys before that age may not be mentally matured and financially secure enough
to take the responsibilities of a family. Thus, one should get married only after a certain age.

Question. 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 these factors other than genes that can cause these variations?
Answer. Height of a child depends upon the genes inherited from parents. However, there
are some other factors also that can affect height. These factors include balanced diet,
hormones, exercise and diseases. Balanced diet is essential for the adolescents as it helps
the bones, muscles and other parts of the body to get adequate nourishment for growth.
Similarly, lack of hormones as growth hormones may lead to dwarfism.
Regular exercise is also essential for healthy muscles, bones and joints and their proper
development. Lack of disease is a priority for growth that is related to other factors listed
above.
Thus, height depends on combination of various factors and the absence or deficiency of any
one of them can cause variations. This is why, tall parents may have short children and vice-
versa.