After ovulation, ___1___ acts on the remaining follicle cells to promote the development of the ___ 2___ , which produces estrogen and large amounts of 3 , which then causes the endometirum to become 4 in preparation for 5 should fertilization of the ovum occur. If the ovum is not fertilized the corpus luteum 6 resulting in a drop of estrogen and progesterone levels. The endometrium then sloughs off in the 7 . The drop in estrogen and progesterone removes the 8 and the GnRH is produced by the 9 and the cycle beings again.