Questions: In which process does the zona pellucida play a critical role? Initiation of folliculogenesis Atresia Ovulation Fertilization

The answer is the last one: Fertilization.

Explanation for each option:

• Initiation of folliculogenesis: The zona pellucida is not directly involved in the initiation of folliculogenesis. This process involves the growth and development of ovarian follicles, which is primarily regulated by hormones.

• Atresia: Atresia is the process of degeneration and resorption of immature ovarian follicles. The zona pellucida does not play a critical role in this process.

• Ovulation: During ovulation, the mature egg is released from the ovarian follicle. While the zona pellucida surrounds the oocyte, it is not directly involved in the process of ovulation itself.

• Fertilization: The zona pellucida plays a critical role in fertilization. It is a glycoprotein layer surrounding the plasma membrane of mammalian oocytes and is essential for sperm binding, prevention of polyspermy, and protection of the developing embryo.

In summary, the zona pellucida is crucial during fertilization, as it facilitates sperm binding and ensures that only one sperm fertilizes the egg.