If egg gets fertilised with sperm, then fertilised egg gets attached with uterus wall and gets nourishment from it. In case, egg is not fertilised, then the inner lining of uterus breaks down and comes out in the form of blood and mucus through the vagina. This cycle occurs every month and is called menstruation.

Why does menstruation occur Class 10 answer?

Every month, the uterus prepares itself to receive the embryo in case fertilization occurs. ... Hence, to discard the unwanted uterine endometrial lining and the egg which is not fertilized, menstruation occurs in human females in a cycle of 28 days.

Why does menstruation occur Why does menstruation occur?

A period happens because of changes in hormones in the body. Hormones are chemical messengers. The ovaries release the female hormones estrogen and progesterone . These hormones cause the lining of the uterus (or womb) to build up.