Which of the following cells undergoes meiosis to produce four sperm?

Correct Answer: C

Rationale: The correct answer is C: Primary spermatocyte. Primary spermatocytes are diploid cells that undergo meiosis to produce four haploid cells, which develop into sperm. First, primary spermatocytes undergo meiosis I to form two secondary spermatocytes. Then, meiosis II occurs in each secondary spermatocyte to produce a total of four spermatids, which eventually mature into sperm. Explanation for why other choices are incorrect: A: Spermatids are already haploid cells formed from the division of secondary spermatocytes, not primary spermatocytes. B: Spermatogonium are diploid cells that divide by mitosis to produce primary spermatocytes, not directly giving rise to sperm. D: Ovum is a female gamete that undergoes meiosis to produce one mature egg cell, not sperm.

Correct Answer: B

Rationale: The correct answer is B: spermatogonia. Spermatogonia are the cells within the seminiferous tubules of the testes that give rise to sperm cells. Testosterone is produced by Leydig cells, not spermatogonia. A is incorrect because the spermatic cord does not produce testosterone. C is incorrect as the testis is the overall organ where the seminiferous tubules are located. D is incorrect as oogonia are female germ cells found in the ovaries, not the testes.

Correct Answer: A

Rationale: The correct answer is A: sperm. Sperm is not a component of semen; it is the male reproductive cell. Semen is composed of fluids from the epididymis, seminal glands, and prostate, which provide nourishment, protection, and transportation for sperm. The epididymis stores and matures sperm, seminal glands produce seminal fluid, and the prostate contributes prostatic fluid. Sperm is only a part of semen and not a component of it. Therefore, choice A is the correct answer.

Correct Answer: C

Rationale: The correct answer is C: blastocyst. At this stage of development, the embryo is a hollow ball of cells with an inner cell mass. This structure is called a blastocyst. A is incorrect because testosterone is a hormone, not a cell structure. B is incorrect as it does not describe the early stage of embryonic development. D is incorrect as luteinizing hormone is a hormone involved in the menstrual cycle, not embryonic development.

Correct Answer: D

Rationale: Step-by-step rationale: 1. Testosterone inhibits the release of luteinizing hormone (LH) through negative feedback. 2. LH is produced by the anterior pituitary. 3. Therefore, testosterone exerts negative feedback on the anterior pituitary to turn off LH secretion. 4. This maintains hormonal balance in the body. Summary of other choices: A. Incorrect because testosterone primarily affects LH secretion, not follicle stimulating hormone (FSH). B. Incorrect as it inaccurately suggests that testosterone turns off both LH and FSH secretion. C. Incorrect because Sertoli cells are involved in spermatogenesis, not LH regulation.