Question 8

Write notes on—
(a) Adam’s apple.
(b) Secondary sexual characters.
(c) Sex determination in the unborn baby.


(a) Adam’s apple:

During the puberty, the larynx grows larger in male in human beings. It can be seen as a protruding part of the throat. This is called as Adam’s apple. Larynx becomes prominent in boys because of sex hormones. Due to which the vocal cords becomes longer and thicker which leads to a hoarse voice. However, the larynx is of small size in females and it is hardly visible. Girls have a high pitched voice because of the smaller size of the larynx.

(b) Secondary sexual characters:

Sex hormones are responsible for secondary sexual characters in males and females. Males and females are distinguished by the sexual characters. At the time of puberty, the secondary sexual characters are the physical and behavioral changes that appears in humans.

Secondary sexual characters that are appears in boys are as follows:

  • Growth of beard
  • Appearance of chest hair
  • Growth of hair in genital area and other part of the skin as well.

Secondary sexual characters that are appears in females are as follows:

  • Increase in the size of breast
  • Growth of hair in genital areas and other parts of the skin too.
  • Voice becomes soft and high pitched.                                                                                                                                                                                                                                                                                                                                                                                                            (c) Sex determination in an unborn baby:

The sex of the baby is determined by the male gamete that fuses with the female gamete.

23 pairs of chromosomes are present in humans. Out of these pair, the last pair is known as the sex chromosomes.

Male have XY sex chromosome and male gamete can be of two types:

22 + X ; 22 + Y

Whereas female has XX chromosomes and type of female gamete:

22 + X

; X is responsible for a baby girl.

Y is responsible for a baby boy.


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