Original sentence: It occurs on a regular basis in reproductive age females of certain mammal species.Menstruation is the shedding of the uterine lining (endometrium).Overt menstruation (where there is bleeding from the vagina) is found primarily in humans and close evolutionary relatives such as chimpanzees
Edited sentence: Menstruation is a natural bodily process in women in which the uterine lining (endometrium) is shed.Overt menstruation (where there is bleeding from the vagina) occurs primarily in humans and close evolutionary relatives such as chimpanzees