The uterine lining begins to break down and bleeding results. Blood some uterine tissue and the unfertilized egg make their way out through the vagina. A. Menstrual phase B. Follicular phase C. Ovulation phase D. Luteal phase
When the follicular phase begins, levels of estrogen and progesterone are low. As a result, the top layers of the thickened lining of the uterus (endometrium) break down and are shed, and menstrual bleeding occurs.
