17. The primary difference between estrous and menstrual cycles is that:
(A) most estrous cycles are of much longer duration compared to 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 across the estrous cycle, whereas in menstrual cycles copulation only occurs during theperiod surrounding ovulation.
(E) the endometrium shed by the uterus during the estrous cycle is reabsorbed, whereas the shed endometrium ofmenstrual cycles is excreted from the body.