Why does menstruation occur?

Explanation

Menstruation is a process in which blood and mucous flows out every month through the vagina This process occurs every month because one egg is released from the ovary every month and at the same time, the uters (womb) prepares itself to receive the fertilized egg. Thus, the inner linning of hte uterus gets thickened and is supplied with blood to nourish the embroy. If the egg does not get fertilized, then the linning of the uterus breaks down slowly and gets released in the form of blood and mucous from the vagina,