The average menstrual cycle is

Correct Answer: D

Rationale: The correct answer is D (28 days) as it is the average length of a menstrual cycle, which is typically counted from the first day of one period to the first day of the next. The menstrual cycle is controlled by hormonal changes and the average duration is around 28 days. This length allows for the proper preparation and shedding of the uterine lining. Choices A, B, and C are incorrect as they do not align with the typical length of a menstrual cycle, which is around 28 days.

Correct Answer: D

Rationale: Step 1: Increased binding of a hormone to plasma proteins reduces the concentration of free hormone in the blood. Step 2: With decreased free hormone levels, there is less hormone available to exert its effects. Step 3: This reduction in free hormone would lead to an increase in the degree of negative feedback exerted by the hormone to regulate its own production. Therefore, the correct answer is D. Summary: A: Increase in plasma clearance of the hormone - Incorrect. Increased binding to plasma proteins would decrease clearance. B: Decrease in half-life of the hormone - Incorrect. Increased binding can prolong the half-life by protecting the hormone from degradation. C: Increase in hormone activity - Incorrect. Increased binding reduces the availability of free hormone, decreasing its activity.

Correct Answer: D

Rationale: The correct answer is D: Ampulla of the fallopian tubes. Fertilization typically occurs in the ampulla of the fallopian tubes, where the sperm meets the egg. The ampulla is the widest part of the fallopian tube, providing the necessary space for fertilization to occur. Sperm must travel through the cervix and uterus to reach the fallopian tubes where fertilization takes place. The ovary is where the egg is released during ovulation but fertilization occurs in the fallopian tubes.

Correct Answer: D

Rationale: The correct answer is D because menopause occurs when the ovaries run out of follicles, which are needed for ovulation and hormone production. This leads to reduced estrogen levels and cessation of menstrual cycles. Choices A and B focus on hormone levels and follicle responsiveness, not the actual follicle count. Choice C is incorrect as progesterone is mainly produced by the corpus luteum after ovulation, not the primary cause of menopause.

Correct Answer: B

Rationale: The correct answer is B: vesicular (Graafian) follicle. A mature ovarian follicle ready for ovulation is called a vesicular follicle. It is the final stage before ovulation. A: primary oocyte is incorrect as it refers to an immature egg cell. C: ovum is incorrect as it refers to a mature egg cell after fertilization. D: corpus luteum is incorrect as it forms after ovulation and is responsible for producing progesterone, not the mature follicle.