Select the correct statement about the uterine cycle.
◦ If fertilization occurs, the corpus luteum is maintained by a hormone secreted by the developing embryo.
◦ The menstrual phase of the cycle is normally from day 1 to day 8.
◦ During the proliferative phase, levels of progesterone rise as the follicle begins to produce more hormone.
◦ During the secretory phase, estrogen levels are at their highest.