At the time of ovulation, each secondary oocyte is surrounded by a single layer of cells known as a(n) ________.

Correct Answer: A

Rationale: The correct answer is A: vesicular (Graafian) follicle. At the time of ovulation, the secondary oocyte is surrounded by this structure, which is a mature follicle containing a fluid-filled antrum. This structure is essential for the release of the oocyte during ovulation. The other choices, B: primary follicle, C: primordial follicle, and D: uterine (fallopian) follicle, are incorrect because primary follicles are immature, primordial follicles are the earliest stage of follicle development, and uterine (fallopian) follicle is not a correct anatomical term.

Correct Answer: C

Rationale: The correct answer is C: cryptorchidism. Cryptorchidism is the condition where one or both testes fail to descend into the scrotum. This leads to impaired spermatogenesis as the temperature in the abdominal cavity is too high for proper sperm production. Phimosis (A) is the narrowing of the opening of the foreskin, unrelated to testicular descent. The acrosomal reaction (B) is a process during fertilization, not related to testicular descent. Cleavage (D) refers to the rapid mitotic cell divisions of the zygote, not associated with testicular descent.

Correct Answer: D

Rationale: Rationale: 1. LH is a hormone released by the pituitary gland. 2. Its main role in females is to trigger ovulation. 3. LH does not directly affect the uterine tubes or breast enlargement. 4. Therefore, the correct answer is D: "LH has no effect on a female." Summary: A, B, and C are incorrect because LH does not promote breast enlargement or affect the uterine tubes. The correct answer, D, is supported by the physiological functions of LH in the female reproductive system.

Correct Answer: D

Rationale: The correct answer is D: rising levels of luteinizing hormone. Luteinizing hormone surge triggers ovulation by stimulating the release of the mature egg from the ovary. This surge is a crucial event in the menstrual cycle. A: Follicle stimulating hormone is involved in follicular development, not ovulation. B: Progesterone levels rise after ovulation, not before. C: Oestrogen levels actually rise before ovulation to trigger the LH surge, so a drop in oestrogen levels would not initiate ovulation.

Correct Answer: D

Rationale: The correct answer is D: the oviduct. Fertilization occurs in the oviduct, specifically in the ampulla region. Sperm meets the egg in the oviduct where fertilization takes place. The other choices, A: the uterus, B: the vagina, and C: the ureter, are incorrect because fertilization does not occur in these locations. The uterus is where the fertilized egg implants and develops into a fetus. The vagina is the passage for sperm to enter the reproductive system. The ureter is a tube that connects the kidney to the bladder, and is not involved in fertilization.