Which of the following statements is correct?

Correct Answer: C

Rationale: Rationale: C is correct because Leydig cells in the testes secrete testosterone, which is essential for stimulating spermatogenesis in the Sertoli cells. Testosterone plays a crucial role in the development and maturation of sperm. A is incorrect because follicle stimulating hormone is secreted by the pituitary gland, not the hypothalamus. B is incorrect because luteinizing hormone is secreted by the pituitary gland, not the hypothalamus. D is incorrect because Leydig cells primarily secrete testosterone, not inhibin.

Correct Answer: D

Rationale: The correct answer is D: vestibular bulbs. The male reproductive system consists of the prostate, testicles, and spermatic ducts, all essential for the production, storage, and transportation of sperm. Vestibular bulbs are actually part of the female reproductive system, involved in sexual arousal, and not found in the male reproductive system. Therefore, it is the only structure listed that is not a part of the male reproductive system.

Correct Answer: C

Rationale: The correct answer is C: the ejaculatory duct. The deferent duct, also known as the vas deferens, joins with the seminal vesicle duct to form the ejaculatory duct. This is where sperm from the testes and fluid from the seminal vesicles combine before entering the urethra during ejaculation. The other choices are incorrect because the seminal vesicle duct does not directly join with the deferent duct, the urethra is not formed by the deferent duct, and the epididymal duct is not involved in the formation of the ejaculatory duct.

Correct Answer: A

Rationale: The correct answer is A because the spermatozoon is indeed the primordial male cell, the precursor to all other male reproductive cells. Choice B is incorrect because the term "microscopic cell" is too broad and does not specifically define the spermatozoon. Choice C is incorrect because spermatozoa are actually formed within the seminiferous tubules of the testes, not the interstitial cells. Choice D is incorrect because spermatozoa are haploid cells, not diploid. Therefore, only choice A accurately describes the nature and origin of the spermatozoon.

Correct Answer: D

Rationale: The correct answer is D because the ovary is indeed the female gonad responsible for producing eggs and releasing female sex hormones like estrogen and progesterone. This is its primary function, making it the most accurate choice. Choice A is incorrect as the ovary's main role is reproductive rather than mixed. Choice B is incorrect as the ovary secretes both female sex hormones and eggs, not just hormones. Choice C is incorrect as ovules are part of the female reproductive system but not the main function of the ovary.