Nokea
During which phase of the ovarian cycle is progesterone circulating in high amounts?
Correct Answer: D
Rationale: During the luteal phase, the corpus luteum forms from the ruptured follicle after ovulation and secretes progesterone at high levels. Progesterone prepares the endometrium for implantation and maintains pregnancy. The proliferative phase (A) is characterized by estrogen dominance, preparing the endometrium for ovulation. The menstrual phase (B) involves shedding of the endometrium due to decreased hormone levels. The ovulatory phase (C) is marked by the release of the egg but not high progesterone levels. Thus, the correct answer is D as it aligns with the physiological events of the ovarian cycle.