Final answer:
Ovulation is most directly due to a spike in levels of luteinizing hormone (LH). The high level of estrogen in the ovaries stimulates the release of a large amount of LH, known as the LH surge. This surge in LH matures the egg and weakens the wall of the follicle, causing the fully developed follicle to release its secondary oocyte.
Step-by-step explanation:
Ovulation is most directly due to a spike in levels of luteinizing hormone (LH). The high level of estrogen in the ovaries stimulates the release of a large amount of LH, known as the LH surge. This surge in LH matures the egg and weakens the wall of the follicle, causing the fully developed follicle to release its secondary oocyte.