Question

Why does menstruation occur? [3 MARKS]

Answer 1

Each point: 1 Mark

1. Menstruation occurs in human females only when the egg is not fertilised by the male sperm.
2. Since the egg is not fertilised, the thick and soft uterus lining having a lot of blood capillaries in it is not required. Thus, the unfertilised ovum disintegrates within a day and the uterus lining also breaks down.
3. As the uterus lining contains a lot of blood vessels so when it sheds, blood along with other tissues is released. This comes out of the vagina in the form of bleeding.