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

Soln:

1. a) Adam’s apple: In human males, the larynx grows larger at the time of puberty and can be seen as a protruding part of the throat. This protrusion is known as Adam’s apple. In boys, under the influence of sex hormones, the larynx becomes prominent. Due to this, the vocal cord becomes thicker and longer, which causes the voice to be hoarse. On the other hand, in females, the larynx is small and hardly visible. Therefore, girls have a high-pitched voice while boys have a deep voice.
2. b) Secondary sexual characters:Characters which usually appear during the phase of puberty are called secondary sexual characteristics. These are the features that help distinguish the male and female bodies from each other.
   Characteristics seen in males: Hoarseness of voice, the appearance of beard, broadness of chest, growth of hair in genital areas.
   Characteristics seen in females: Start of the menstrual cycle, growth of breasts, growth of hair in the genital areas.
3. c) Sex determination in the unborn baby:The sex of an unborn baby depends upon the pair of sex chromosomes that are present in the cells of the baby.
   X and Y chromosomes are the sex chromosomes in humans. Ovum always contains X chromosome, and male sperm may carry either the X chromosome or Y chromosome. Male genetic make-up is 44 autosomes + XY chromosome, and female genetic make-up is 44 autosomes + XX chromoses.