The follicular phase of the menstruation cycle occurs:

Explanation

Follicular Phase (Days 6-14): The early follicular phase overlaps with the menstrual phase. After menstruation, the ovaries begin to develop several ovarian follicles, each containing an immature egg (oocyte). Follicle-stimulating hormone (FSH) stimulates the growth of these follicles. As the follicles grow, they produce increasing amounts of estrogen. As estrogen levels rise, it stimulates the thickening and growth of the endometrial lining in the uterus. One dominant follicle usually becomes the primary focus, and the others degenerate. The rising estrogen levels also contribute to the negative feedback loop on FSH, preventing the development of additional follicles.