Question

What happens to the walls of uterus during Menstruation ?

Answer 1

the unfertilized egg is removed in the form of blood and mucus..

Answer 2

DURING menstruation a females uterus gets ready to implant an sperm in the upcoming ova from ovary and to provide safety.

but when the ova/egg doesnt get fertilized with the sperm the egg colides with the mucus released by uterus to protect egg.and this uterus breaks of in contact with unfertilised egg and mucus lining worn off through vagina in form of blood.

hope it helps.......