Answer:
see below
Step-by-step explanation:
- If fertilisation does not occur then the ovum disintegrates and endometrial lining of the uterus breaks down . It comes out of the vagina in form of menses .
- If fertilisation does not occur corpus luteum disintegrates. Due to this the progesterone secretion stops which is necessary for the maintaining the endometrial lining.
- This phase is called Menstrual phase , it usually last for 3-5 days .