Which of the following is a true statement?

Question

Quizplus · Accepted Answer

Option A is incorrect because not all mammals have menstrual cycles. For example, most non-human primates, rodents, and rabbits have oestrous cycles instead. 
Option C is incorrect because oestrous cycles occur less frequently than menstrual cycles in most species. 
Option D is incorrect because ovulation occurs after the endometrium thickens in oestrous cycles. Therefore, the only true statement is B, which correctly describes the difference between menstrual and oestrous cycles.

Which of the Following Is a True Statement