Question

What changes are observed in the uterus: 
(i) Subsequent to the implantation of the zygote and 
(ii) If an egg does not get fertilized?

Hint:

If fertilization does not occur, the body goes through the menstrual cycle to shed the unused egg and uterine lining.

Answer 1

- F₂After zygote implantation: The uterus thickens to support the pregnancy. Progesterone and other hormones maintain the uterine lining.
- F₂If fertilization fails: The uterus sheds its lining during menstruation, and the menstrual cycle restarts. The unfertilized egg is eliminated with the uterine lining.