Question

A difference between oestrus and menstrual cycles is that ______.

Options

• non-mammalian vertebrates have oestrus cycles, whereas mammals have menstrual cycles.

• the endometrial lining is shed in menstrual cycles but reabsorbed in oestrus cycles.

• oestrus cycles occur more frequently than menstrual cycles do.

• ovulation occurs before the endometrium thickens in oestrus cycles.

Answer 1

A difference between oestrus and menstrual cycles is that the endometrial lining is shed in menstrual cycles but reabsorbed in oestrus cycles.