The Primary Difference Between Oestrous and Menstrual Cycles Is That

The primary difference between oestrous and menstrual cycles is that ________.

A) the endometrium shed by the uterus during the oestrous cycle is reabsorbed with no extensive fluid flow out of the body, whereas the shed endometrium of menstrual cycles is excreted from the body
B) behavioural changes during oestrous cycles are much less apparent than those of menstrual cycles
C) season and climate have less pronounced effects on oestrous cycles than they do on menstrual cycles
D) copulation normally occurs across the oestrous cycle, whereas in menstrual cycles copulation only occurs during the period surrounding ovulation