I belive the answer is all of the above
We have been able to see more of the cell in detail. We dont have to guess about things because we can see how it works. The more we see the more theories change because we know more.
The uterine lining of the female's uterine cycle is shed during the menstrual phase. Menstrual cycle is a reoccurring cycle which begins at menarche and ends at menopause. During menstrual cycle, the endometrial lining prepares for pregnancy.
