Very Short Answers - Reaching the Age of Adolescence, Science, Class 8 | Science Class 8 PDF Download

Q1: When does the growth start in humans?

 Ans: Growth begins from the day the child is born.

Q2: When do sudden and noticeable changes begin in humans?

Ans. The sudden and noticeable changes begin in humans in adolescence age.
 

Q3: What do the changes in the body of a child indicate?

Ans: The changes in the body of a child indicate that a child is on the way to become an adult.
 

Q4: What is the age of adolescence in humans?

Ans: The age between 11 to 18 or 19 years is called the age of adolescence.
 

Q5: What is puberty?

Ans: The age at which boys and girls become capable of reproduction.
 

Q6: What changes occur during puberty?

Ans: At the time of puberty, the bones of the arms and the legs elongate and make a person tall.
 

Q7: Do both boys and girls grow at the same rate?

Ans. No, girl grows faster than boys.
 

Q8: Do all the parts of the body grow at the same rate?

Ans. No, all the parts of the body do not grow at the same rate.
 

Q9: Which organ is called a voice box?

Ans: Larynx.
 

Q10: What is Adam’s apple?

Ans: The protruding part of the throat in boys is called Adam’s apple.
 

Q11:  Name the main male and female reproductive organs.

Ans: Testes are the main male reproductive organs and ovaries are the main female reproductive organs.
 

Q12: What are hormones?

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

Q13: Name the male hormone.

Ans: Testosterone.
 

Q14: Name the female hormone.

Ans: Estrogen.
 

Q15: What is the name of the endocrine gland that controls the production of these male and female hormones?

Ans: Pituitary gland.
 

Q16: What is the puberty age in females?

Ans: 10 to 12 years.
 

Q17: What do you mean by menarche?

Ans: The first menstrual flow indicates menarche.
 

Q18: What is menopause?

Ans: Stoppage of menstruation is called menopause.
 

Q19: What are chromosomes?

Ans: The thread-like structures in the nucleus are called chromosomes.

Q20: How many chromosomes are there in human cell?

Ans: There are 23 pairs of chromosomes in the nucleus of human cell.
 

Q21: What are sex chromosomes?

Ans: Out of 23 pairs, one pair of chromosomes is called sex chromosomes.
 

Q22: What are the names of these sex chromosomes?

Ans: Sex chromosomes are named as X and Y.
 

Q23: What are the chromosomes in females and males?

Ans: A female has two X chromosomes while a male has one X and one Y chromosomes.
 

Q24: What types of chromosomes occur in egg (female gamete)?

Ans: The egg always has one X chromosome.
 

Q25: What types of chromosomes occur in sperms?

Ans: Sperm has only X chromosome or only Y chromosome.
 

Q26: How many types of sperms are there?

Ans: Sperms are of two types: (i) One kind has X chromosomes. (ii) Other kind has Y chromosomes.
 

Q27: Who is responsible for the sex determination of a child—mother or father?

Ans. The sex chromosomes of father determine the sex of an unborn baby.
 

Q28: Name some endocrine glands other than the pituitary gland.

Ans: Some endocrine glands are the thyroid, pancreas, and adrenals.
 

Q29: Name the hormone produced by the thyroid gland.

Ans: Thyroxine.
 

Q30: What is the name of the hormone produced by the pancreas?

Ans: Insulin is the hormone produced by pancreas.
 

Q31: Name the disease caused by less or not secretion of thyroxine hormone by the thyroid.

Ans: Goitre.
 

Q32: Name the disease caused by less secretion of insulin hormone by the pancreas.

Ans: Diabetes.
 

Q33: What is the name of the hormone produced by the adrenal gland?

Ans: Adrenalin.
 

Q34: What is the function of adrenalin hormones?

Ans: Adrenalin hormone maintains the correct balance of salts in the blood.
 

Q35: Name the hormone which is necessary for the normal growth of a person.

Ans: Growth hormone.
 

Q36: Which endocrine gland produces the growth hormone?

Ans: Pituitary gland.
 

Q37: What do you mean by metamorphosis?

Ans: The change from larva to an adult is called metamorphosis. 

Q38: Name the hormone which controls metamorphosis in frog.

Ans: Thyroxine hormone which is produced by thyroid controls the metamorphosis in frogs.
 

Q39: Name the element that is essential to produce thyroxine hormone.

Ans: Iodine.
 

Q40: What happens if there is no iodine present in water?

 Ans: If there is no iodine present in water, the tadpole cannot become adult.
 

Q41: What do you mean by health?

Ans. The physical and mental well being of a person is called health.
 

Q42: How can we keep our body healthy?

Ans. To keep the body healthy every one needs to have a balanced diet.
 

Q43: What do you understand about a balance diet?

Ans. The food containing proteins, carbohydrate, fats and vitamins in requisite proportions is called balanced diet.
 

Q44: Why does mother’s milk is considered a better diet for infants?

Ans: Mother’s milk provides all the nutrients that they need. So mother’s milk is better food for infants.
 

Q45: What is the function of iron?

Ans: Iron helps to make the blood (haemoglobin in blood).
 

Q46: Name some iron-rich food items.

Ans. Leafy vegetables, jaggery, meat and citrus fruits are rich in iron.
 

Q47: What do you mean by personal hygiene?

Ans: To keep themselves neat and clean by washing of clothes and by bathing is called personal hygiene.
 

Q48: What happens if cleanliness is not maintained?

Ans: If cleanliness is not maintained then there are chances of catching bacterial infection.
 

Q49: Name the causative organisms of AIDS.

Ans: It is a virus called HIV.
 

Q50: What is the legal age for marriage for girls and boys?

Ans: The legal age for marriage is 18 years for girls and 21 years for boys.