Answer: Oestrus cycle.
- A Oestrus cycle
- B a plain menstrual cycle
- C only the lunar cycle
- D some fixed diurnal one
Correct answer: A. Oestrus cycle
Explanation: Non-primate mammals show the oestrus cycle of reproductive activity.
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.