Microscopic anatomy of testis and ovary

Correct answer: B. Seminiferous tubules

Explanation: Spermatogenesis is the production of sperm and occurs mainly in the seminiferous tubules of the testes. Germ cells develop there with support from Sertoli cells, while Leydig cells between the tubules produce testosterone. The epididymis is mainly for maturation and storage, the vas deferens transports sperm, and the prostate adds fluid; therefore, option B is correct.

Correct answer: A. To nourish and support developing sperm cells

Explanation: Sertoli cells lie within the seminiferous tubules and nourish, support, protect, and regulate developing germ cells during spermatogenesis. They also help form the blood-testis barrier and release regulatory substances. Leydig cells, not Sertoli cells, mainly secrete testosterone. Ova are formed in ovaries and milk is produced by mammary glands, so option A is correct.

Correct answer: A. Acrosome

Explanation: The acrosome is a cap-like vesicle at the anterior end of the sperm head. It contains enzymes, including hydrolytic enzymes, that help the sperm penetrate the coverings of the secondary oocyte during fertilisation. The nucleus stores paternal genetic material, mitochondria occur mainly in the middle piece, and the flagellum provides movement; therefore, option A is correct.

Correct answer: C. Ampullary-isthmic junction of the oviduct

Explanation: In humans, fertilisation normally occurs at the ampullary-isthmic junction of the oviduct. Sperm meet and fuse with the secondary oocyte at this site, forming a zygote. The ovary releases the oocyte, the uterus is the usual site of implantation and later development, and the vagina is the copulatory canal rather than the normal fertilisation site; therefore, option C is correct.

Correct answer: A. Lactation

Explanation: Lactation is the production and secretion of milk by the mammary glands, usually beginning around childbirth and continuing under hormonal control. Prolactin promotes milk synthesis, while oxytocin causes contraction of myoepithelial cells and helps eject milk. Ovulation releases an oocyte, implantation embeds an embryo in the uterine lining, and cleavage divides the early zygote. Thus, option A is correct.

Correct answer: A. A mature ovarian follicle

Explanation: A Graafian follicle is the fully mature, late-stage ovarian follicle that contains a secondary oocyte surrounded by follicular cells and follicular fluid. At ovulation, the follicle ruptures and releases the secondary oocyte; the remaining follicular tissue later contributes to the corpus luteum. It is therefore neither a male gland, a sperm structure, nor an umbilical cord. Option A is correct.