Topic outline

    • Reaching the Age of Adolescence

      Q22. Who attains puberty at an earlier age in human beings: boys or girls?

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


      Q23. What is the most conspicuous change during puberty?

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


      Q24. What is the legal age for marriage of boys and girls in our country?

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

      Q25. How do hips of girls change during puberty?

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


      Q26. State the age at which adolescence usually begins and the age up to which it lasts.
      At what age adolescence usually begins and up to which it lasts?

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


      Q27. Why endocrine glands are called ductless glands?

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


      Q28. Which hormone is responsible for metamorphosis in frog?

      Ans. In a frog, metamorphosis is controlled by thyroxine, the hormone produced by thyroid.


      Q29. Which two male sex organs develop completely at puberty?

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

      Q30. Which two female sex organs develop completely at puberty?

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


      Q31. What is puberty?

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


      Q32. What are hormones? Where are hormones made in the human body?

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


      Q33. What is the function of adrenalin hormone in the body?

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

      Q34. Name the time period in one's life when the brain has the greatest capacity for learning.

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


      Q35. Which disease is caused by the insufficient production of insulin hormone by pancreas?

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


      Q36. Which endocrine gland secretes hormone that maintains correct salt balance in the blood?

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


      Q37. Why is exercise important during adolescence?

      Ans. 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.

      Q38. What is the effect of a smaller voice box in grown up girls?

      Ans. 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.


      Q39. Why is iron mineral important for our body? Write some iron rich foods.

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


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