Question

Explain why it makes sense that the levels of estrogen and progesterone are low in blood of a female during menstruation

Answer 1

Answer:

At the beginning of the follicular phase, the lining of the uterus (endometrium) is thick with fluids and nutrients designed to nourish an embryo. If no egg has been fertilized, estrogen and progesterone levels are low. As a result, the top layers of the endometrium are shed, and menstrual bleeding occurs.