Answer: 28 days.
- A 21 days
- B 28 days
- C 35 days
- D 14 days
Correct answer: B. 28 days
Explanation: The average menstrual cycle is 28 days, though normal range is 21-35 days. It is counted from the first day of menstruation to the first day of the next period.
The human male reproductive system: sperm formed in the testis mature in the epididymis and travel via the vas deferens, mixing with secretions of the seminal vesicle, prostate and bulbourethral glands. Image: Wumingbai, CC BY-SA 4.0, via Wikimedia Commons.
Concept context
Male and female reproductive systems, gametogenesis, fertilization, implantation, pregnancy, and reproductive health.