What structure in the male reproductive system stores sperm until ejaculation?

Correct Answer: A

Rationale: The correct answer is A: Epididymis. The epididymis is a tightly coiled tube where sperm are stored and matured until ejaculation. It allows for the concentration and storage of sperm produced by the testes. The other choices are incorrect because: B: Seminal vesicles produce a fluid that nourishes and protects sperm, not store sperm. C: Vas deferens transports sperm from the epididymis to the urethra, but doesn't store sperm. D: Prostate gland produces a fluid that mixes with sperm to form semen, but does not store sperm.

Correct Answer: A

Rationale: The mucous plug in the cervix during pregnancy serves to prevent infection by acting as a physical barrier, blocking the entry of harmful pathogens into the uterus and protecting the developing fetus. It does not facilitate sperm transport, as sperm travel through the cervical canal before pregnancy. It also does not enhance uterine contractions or nourish the embryo, as those functions are carried out by other mechanisms in the body during pregnancy.

Correct Answer: D

Rationale: Correct Answer: D - Progesterone Rationale: 1. Progesterone maintains the uterine lining for implantation and supports fetal development. 2. It inhibits contractions to prevent premature labor. 3. Estrogen helps with fetal development but is not the primary hormone during pregnancy. 4. Prolactin is responsible for milk production after birth, not fetal development. 5. hCG is produced early in pregnancy but does not directly support fetal development.

Correct Answer: A

Rationale: Estrogen is the correct answer as it is the primary hormone responsible for the development of female reproductive organs like the ovaries, uterus, and breasts. Estrogen plays a crucial role in regulating the menstrual cycle and supporting pregnancy. Testosterone is a male sex hormone. Progesterone is important for maintaining pregnancy and regulating the menstrual cycle. FSH (Follicle-stimulating hormone) stimulates the growth of ovarian follicles but is not directly involved in the development of female reproductive organs.

Correct Answer: A

Rationale: The correct answer is A: Nourish the embryo. During pregnancy, the uterine lining, also known as the endometrium, thickens to provide a rich blood supply and nutrients to support the developing embryo. This lining helps in implantation and facilitates the exchange of oxygen, nutrients, and waste products between the mother and the embryo. Choice B is incorrect as uterine contractions are primarily controlled by the muscles of the uterus. Choice C is incorrect because the uterine lining does not directly support the fetus during delivery; rather, it is the uterine muscles that aid in labor. Choice D is incorrect as the placenta, not the uterine lining, is responsible for providing nutrients to the fetus.