AP BIOLOGY

Detailed explanation-1: -The secondary oocyte completes meiosis II only when fertilized by a spermatozoan. After fertilization is initiated, the secondary oocyte begins its second meiotic division, resulting in the formation of a mature ovum and another polar body. At this point, the ovum is ready to fuse with the spermatozoan.

Detailed explanation-2: -Answer and Explanation: The secondary oocyte, arrested in metaphase II, is ovulated from the ovary and moves into the oviduct. If fertilization does not occur, this secondary oocyte will move through the female’s reproductive tract and be lost during menstruation.

Detailed explanation-3: -Ovulation and Fertilization After 12–14 days, when the follicle is mature, it bursts open, releasing the secondary oocyte from the ovary. This event is called ovulation (see Figure above). The follicle, now called acorpus luteum, starts to degenerate, or break down .

Detailed explanation-4: -Soon afterward, the first meiotic division occurs, and the mature ovum is released from the ovary by a process called ovulation. The ovulated egg is in second meiotic metaphase when it is released (Figure 19.24).