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.