Instead of menstruating every month, why is the uterine lining (endometrium) not sustained continuously throughout the life of a woman from puberty to menopause?

The theory formulated by Crystal, the teacher, is that it would require a lot of energy to sustain the endometrium continuously, and from an evolutionary point of view, this is not very efficient for the body.

In order to guide students towards an explanation for this question, Crystal provided guiding questions: Why do women undergo menstruation? What is the uterine lining used for? What causes the uterine lining to grow and thicken? Why can the uterus be a good environment for bacteria to grow? How can it affect the woman when microbes grow in the uterus?

Here is the KF view generated: