1.      How does fertilisation take place? Fertilisation occurs once in a month. Comment.

Once in a month one egg is released from either of the ovaries. The egg gets transferred to fallopian tube from the ovaries. Sperms swims towards fallopian tube and only one sperm can penetrate the egg at a time. This process is called fertilization. A menstrual cycle is composed of about 28 days. This means only one egg is available for fertilization in one menstrual cycle. Hence, it can be said that fertilization can occur only once in a month.