The gonads, or primary sex organs, produce sex cells, also known as ________.

Correct Answer: C

Rationale: The correct answer is C: gametes. Gonads produce sex cells, which are haploid cells involved in reproduction. Gametes are the mature, haploid male or female germ cells (sperm or egg) produced by the gonads. Zygotes are formed when gametes fuse during fertilization, not produced by gonads. Interstitial cells are found in the testes and produce hormones, not sex cells. Spermatids are immature male germ cells that develop into sperm, not the primary sex cells produced by gonads.

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: C

Rationale: The secretory phase follows ovulation in the menstrual cycle. During this phase, the corpus luteum, formed from the ruptured follicle, secretes progesterone, maintaining the endometrium for potential implantation of a fertilized egg. Choice A is incorrect as ovulation occurs in the preceding phase (ovulatory phase). Choice B is incorrect as the functional layer of the endometrium thickens during the secretory phase to support a potential pregnancy. Choice D is incorrect as the functional layer of the endometrium is not shed during the secretory phase, but rather maintained for pregnancy support.

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.