(a) Fetilization: When sperms and eggs from the opposite partners (males and females) fuse to form Zygote. It is called fertilization.
(b) Implantation: The fertilised egg (zygote) soon starts developing and by the time it reaches the **, a small ball of numerous cells is already formed. This is a kind of embryo which forms a pit in the wall of the ** and gets fixed in it. This natural way of fixing of the embryo in the wall of the ** is called implantation. This produces the state of pregnancy.
(c) Puberty: Puberty is the ** during which the reproductive systems of boys and mature. In , it starts at the age of about ten and the first sign of puberty is the development of breasts. In boys, it starts at about 11 years of age of the^enlargement of the testes is its first sign. Sudden spurt in growth, shoulder girdle grows more than hip girdle.
