(1) Testosterone
(2) Thyroid
(3) Adam's apple, Adolescence
(4) Endocrine
(5) Target sites
(6) Larynx
(7) Pituitary, Puberty
(8) Hormone
(9) Insulin
(10) Estrogen.

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 set age.

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, 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 proper development lack of disease is a priority for proper growth that is related to other factors listed above. Thus, height depends on combination of various factors.

(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 character 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

(a) A specific pair of chromosomes determine the sex of the individual. These are called sex chromosomes, named X and Y.
(b) No, the belief that the mother is responsible for the sex of her baby is completely wrong and to blame her for this is totally unjustified.
It is because the sex chromosomes of the father determine the sex of an unborn baby.
(c) Strong and determined personality with responsibility towards the family and respect for elders.

Body changes during adolescence are given below

(a) The dotted line represents the height of boys.
(b) The solid line represents the height of girls.
(c) At the on-set 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.

(a) Some of the changes are
(i) Increase in height.
(ii) Change in body shape.
(iii) Voice change.
(iv) Development of sex organs.
(v) Hairy line above the lips.
(b) This special period of life is known as adolescence. During this period, body undergoes changes leading to reproductive maturity.
(c) At puberty, the larynx beings to grow so that boys develop larger voice boxes. Sometimes, the muscles of the growing voice box go out of control and the voice becomes hoarse.
(d) Hormones (i.e. testosterone in this case) is responsible for these changes.
(e) The teacher is patient, observant and devoted to his duty.

We conclude that initially, girls grow faster than boys but by about 18 years of age, both reach at their maximum height. The rate of growth in height varies in different individuals.

(a) Adam's apple The protruding part of the growing voice box is called Adam's apple in males. In boys, voice box (larynx) develops larger than girls and this protruding part is seen as bulge in the neck area.
(b) Secondary sexual characters The physical features that help to distinguish the males from the females are called secondary sexual characters. These characters develop at the time of puberty. The secondary sexual characteristics in humans are given below:
In males,
(i) Growth of pubic hair, beard and moustaches.
(ii) Hair on chest and underarms.
In females,
(i) Enlargement of breasts.
(ii) Appearance of pubic hair, hair under arms.
(c) Sex determination of the unborn baby Sex of the unborn baby is determined by the sex chromosomes, i.e. X and Y. A female has two X-chromosomes, while a male have one X and one Y-chromosome.
So in females, the gamete, i.e. egg have only one X-chromosome but in males, the sperm, i.e. male gamete may have an X-chromosome or V-chromosome. If the egg fertilises with sperm containing X-chromosome, the zygote will develop into a female (XX) and if the egg fertilises with sperm containing V-chromosome, the zygote will develop into a male (XY).