Menstruation
A) is triggered by an LH surge.
B) is triggered by HCG.
C) is triggered by an increase in the levels of estrogen and progesterone.
D) coincides with the beginning of the pre-ovulatory phase of the ovarian cycle.

Question

Quizplus · Accepted Answer

Menstruation marks the beginning of the menstrual cycle and coincides with the start of the follicular or pre-ovulatory phase, where the uterine lining sheds due to a drop in estrogen and progesterone levels.