The primary difference between estrous and menstrual cycles is that ________.
A) in the absence of pregnancy, the endometrium is reabsorbed in estrous and shed in menstrual cycles
B) behavioral changes during estrous cycles are much less apparent than those of menstrual cycles
C) season and climate have less pronounced effects on estrous cycles than they do on menstrual cycles
D) copulation normally occurs throughout the estrous cycle, whereas in menstrual cycles copulation only occurs during the period surrounding ovulation

Question

Quizplus · Accepted Answer

The primary difference between estrous and menstrual cycles lies in how the endometrium (the lining of the uterus) is handled in the absence of pregnancy. In species with estrous cycles, the endometrium is reabsorbed by the body, whereas in species with menstrual cycles, such as humans, the endometrium is shed through menstruation.

The Primary Difference Between Estrous and Menstrual Cycles Is That