Question

what changes are observed in the uterus if fertilisation does not occur?​

Answer 1

Explanation:

also, the uterus prepares itself by forming a thick and spongy lining to receive the fertilized egg. If the egg is not fertilized during this time, the lining of the uterus (endometrium) is shed along with blood and mucus. This is known as menstruation and it is a 28-day long cycle.

Answer 2

Answer:

If the fertilisation does not occur the endometrium along with blood and mucus from the vagina and cervix made up the menstrual flow that leaves the body through the vagina during the period.

Explanation:

If it is not clear you can search in google or youtube.