Question

Which of the following is NOT associated with the human menstrual cycle?

• A. Hormonal changes
• B. Vaginal cytology changes
• C. Estrus profile
• D. Endometrial changes

Hint:

Humans menstruate; the term that belongs to non-primate mammals is the odd one out.

Answer 1

The Correct Option is C

Step 1: Recall what defines the human reproductive cycle. Primates, including humans, have a MENSTRUAL cycle, characterised by cyclical shedding (menstruation) of the endometrium when fertilisation does not occur.
Step 2: Identify what an estrus (oestrous) cycle is. Estrus is the reproductive cycle of most non-primate mammals, in which there is a discrete period of heat (sexual receptivity) and the endometrium is reabsorbed rather than shed; humans do NOT have an estrus cycle.
Step 3: Match the genuine components of the menstrual cycle. Cyclical hormonal changes (FSH, LH, estrogen, progesterone), endometrial changes (proliferative then secretory phase, then menstruation), and vaginal cytology changes (shifting epithelial cell maturation with estrogen) all occur as part of the menstrual cycle.
Step 4: Apply the exception logic. The feature that does NOT belong to the human menstrual cycle is the estrus profile, which is a property of non-primate mammals.
Step 5: Hence the answer is the estrus profile.