The __________________ is a thick, muscular organ that can expand to accommodate a developing baby.

Correct Answer: A

Rationale: The correct answer is A: Uterus. The uterus is a thick, muscular organ located in the lower abdomen where a developing baby grows during pregnancy. It can expand significantly to accommodate the growth of the fetus. The ovaries (B) are responsible for producing eggs, not for accommodating a developing baby. The vulva (C) refers to the external female genitalia, not the organ that supports pregnancy. The breast (D) is responsible for producing milk after childbirth, not for housing a developing baby.

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.

Correct Answer: C

Rationale: The correct answer is C because the Fallopian tubes are indeed located between the ovary and the uterus. This is essential for the transportation of the released ovum from the ovary to the uterus for possible fertilization. Choice A is incorrect as the Fallopian tubes are not solely muscular-membranous ducts; they have ciliated epithelial cells aiding in the movement of the ovum. Choice B is too broad, as the Fallopian tubes are just one part of the female reproductive system. Choice D is incorrect because the Fallopian tubes do not capture the ovule; rather, they provide a pathway for its transport.