___________is an organelle that helps the sperm to penetrate the ovum.

Correct Answer: A

Rationale: The correct answer is A: Acrosome. The acrosome is an organelle in the head of the sperm that contains enzymes which help the sperm penetrate the outer layer of the ovum during fertilization. It plays a crucial role in the fertilization process. Explanation of other choices: B: Zona pellucida is the outer membrane of the ovum that the sperm needs to penetrate, not an organelle within the sperm itself. C: Megalis is not a relevant organelle involved in fertilization. D: None of the above is incorrect as the acrosome is the specific organelle that aids in sperm penetration of the ovum.

Correct Answer: B

Rationale: The paraurethral (Skene's) glands are responsible for secreting mucus to facilitate lubrication during sexual arousal. This mucus aids in lubricating the urethra and providing moisture for sexual intercourse. Estrogen (Choice A) is a hormone produced by the ovaries and not directly related to the function of Skene's glands. Testosterone (Choice C) and androgens (Choice D) are male sex hormones and are not involved in the secretion of mucus by Skene's glands. Therefore, the correct answer is B, mucus, as it aligns with the known function of the paraurethral glands.

Correct Answer: A

Rationale: The female reproductive system arises from Paramesonephric (Mullerian) ducts. These ducts develop into the fallopian tubes, uterus, and upper part of the vagina. Initially present in both sexes, in females, they persist and differentiate into the female reproductive organs under the influence of estrogen. Mesonephric (Wolffian) ducts develop into male reproductive structures. Aldosterone is a hormone related to electrolyte balance and has no direct role in female reproductive system development. FSH (Follicle-Stimulating Hormone) is a pituitary hormone that stimulates ovarian follicle development but does not play a role in the initial development of the female reproductive system.

Correct Answer: A

Rationale: Rationale: A chancre is a painless ulcer that is characteristic of primary syphilis infection. It usually appears on the external genitalia as a result of Treponema pallidum infection. This is distinct from the other conditions listed: Gonorrhea presents with urethritis and discharge, Trichomoniasis with vaginal discharge and irritation, and Herpes genitalis with painful vesicles or ulcers. Syphilis is the only condition among the choices that typically presents with a chancre on the external genitalia.

Correct Answer: D

Rationale: The correct answer is D: parturition. Parturition refers to the process of giving birth. It involves the series of events that lead to the expulsion of the fetus from the mother's womb. Lactation (choice A) is the production of milk by the mammary glands after birth. Gestation (choice B) is the period of development of the fetus in the womb. Micturition (choice C) is the process of urination and is not related to childbirth. Therefore, the term that specifically describes the process of giving birth is parturition.