Ovulation, the release of an egg, is a rapid event. The egg is typically viable for fertilization for approximately 12-24 hours after its release.

Here are the answers to your questions:

1. Ovulation, the release of an egg, is a rapid event. The egg is typically viable for fertilization for approximately 12-24 hours after its release.
2. Menstruation is the monthly shedding of the uterine lining (endometrium) through the vagina. This process occurs when a fertilized egg does not implant in the uterus, marking the beginning of a new menstrual cycle.
3. Menstruation is regulated by hormones. Specifically, the cycle is controlled by the interplay of Follicle-Stimulating Hormone (FSH), Luteinizing Hormone (LH), estrogen, and progesterone.