Answer: After a sperm enters it.
- A Before puberty
- B At ovulation
- C During implantation
- D After a sperm enters it
Correct answer: D. After a sperm enters it
Explanation: The secondary oocyte is arrested in metaphase of meiosis II and completes this division only if and when a sperm penetrates it.
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.