Answer: oestrus cycle.
- A menstrual cycle
- B diurnal cycle
- C oestrus cycle
- D cardiac cycle
Correct answer: C. oestrus cycle
Explanation: Non-primate mammals show oestrus cycles; only primates (including humans) show menstrual cycles.
Structure of a mature flower. Image: LadyofHats (Mariana Ruiz), Public Domain, via Wikimedia Commons.
Concept context
Asexual and sexual reproduction, flower anatomy, pollination, fertilization, and seed development.