Pawan Prajapati
Last Activity: 3 Years ago
1)In boys the voice changes due to better growth of larynx, which protrudes on the throat forming Adam’s apple. Thus, the voice becomes deep and hoarse.
2) Secondary sex characters develop-
In both, boys and girls, hair starts growing in arm pits and the pubic region.
In boys moustache and beard appear. In girls, oestrogen makes the breasts develop with milk secreting glands inside.
3) The sex of the baby is determined by the XX and XY chromosomes in a zygote. X chromosome stands for female and Y chromosome for male character. When X and X chromosomes form zygote (XX) the baby is female. When X and Y chromosomes form zygote (XY) the baby is male.