Answer: This is because of the secretion of sex hormones which bring about change in the body.
Q. Why physical exercise and balanced diet are essential during adolescence.
Answer: Adolescence is a stage of rapid growth and development. Hence to keep body healthy and fit, physical exercise and balanced diet are essential during adolescence.
Q. Why adrenaline hormone is called emergency hormones?
Answer: This is because it prepares body to fight and to run fast. It also helps the body to adjust to stress when one is very angry, embarrassed or worried.
Q. What is the term used for secretions of endocrine glands responsible for changes taking place in the body?
Answer: Hormones is the term used for secretions of endocrine glands responsible for changes taking place in the body.
Q. Sweat gland secretes more during adolescence. Why?
Answer: During adolescence, sebaceous glands enlarge and produce more sebum under the influence of hormones called androgens.
Q. What will happen if a person does not take iodized salts?
Answer: Deficiency of iodine in diet causes hypothyroidism due to which thyroid gland increase in size forming exopthalmic goiter.
Q. Why do acne and pimple appear during adolescence?
Answer: This is because of the increased activity of sebaceous glands (oil glands) in the skin. Sebaceous glands produce a substance called sebum, which is responsible for keeping the skin and hair moisturized. If sebum gets trapped in the pore, acne can develop.
Q. Some gland does not have duct. How are their secretion transported in the body?
Answer: Gland that does not have duct is called ductless gland like Endocrine glands. These gland release hormones directly into the blood stream. The blood transports their secretion in the body to target organ.
Q. Give reasons for the following
(a) Tadpoles growing in iodine deficient water have retarded growth.
Answer. The process of growth and development is regulated by thyroxine hormone which is produced by thyroid gland. Iodine is required for thyroxine production. That is why retarded growth is seen in tadpoles living in iodine deficient water.
(b) Voice becomes hoarse in adolescent boys.
Answer. Sometimes the muscles of the growing voice box go out of control and the voice becomes hoarse.
(c) Females have no role in determining gender of a child.
Answer. Male has both X and Y chromosomes but a female has only two X chromosomes . When sperm containing Y chromosomes fertilize the egg leads to a boy off spring (XY) . Hence, Females have no role in determining gender of a child.
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