The opening to the uterus:

Correct Answer: C

Rationale: The correct answer is C: Cervix. The cervix is the opening to the uterus, allowing passage of sperm into the uterus and menstrual blood out of the uterus. The vagina (A) is the canal leading from the cervix to the outside of the body. The ovary (B) is responsible for producing eggs and hormones but is not the opening to the uterus. Hypermenorrhoea (D) refers to excessive menstrual bleeding and is not related to the opening to the uterus.

Correct Answer: C

Rationale: The correct answer is C because the endocrine role of the testicle primarily involves the secretion of testosterone. Testosterone is the main androgenic hormone produced by the testicles, which plays a crucial role in various physiological functions such as the development of male reproductive organs, sperm production, and secondary sexual characteristics. Choice A is incorrect because while interstitial cells (Leydig cells) are involved in the production of testosterone, the endocrine role of the testicle is not limited to these cells alone. Choice B is incorrect as it is too general. While androgenic hormones are indeed secreted by the testicles, testosterone specifically is the main androgenic hormone produced by them. Choice D is incorrect as the maturation of sex organs is primarily regulated by the action of testosterone but is not the sole endocrine role of the testicle.

Correct Answer: D

Rationale: The correct answer is D: seminal vesicles. Seminal vesicles are accessory glands that produce a significant portion of the fluid that makes up semen. They contribute nutrients and substances that support sperm viability and motility. Choices A, B, and C are incorrect as they are structures of the penis involved in erection and urination, not accessory glands of the male reproductive system.

Correct Answer: A

Rationale: Step-by-step rationale for choice A being correct: 1. Sperm cells need to be mobile to reach the egg for fertilization. 2. Seminal fluid provides the environment for sperm motility. 3. Sperm cells acquire motility in the seminal fluid due to specific nutrients and ions present. Summary of why other choices are incorrect: - Choice B: Being microscopic is a general characteristic of sperm cells but not specific to their mobility. - Choice C: Sperm cells are stored in the epididymis, not the "crotum." - Choice D: Sperm cells are all of the same kind, not three different kinds.

Correct Answer: C

Rationale: Step 1: The ovary is a complex organ with distinct internal structures. Step 2: The ovarian cortex houses ovarian follicles, which are crucial for reproductive functions. Step 3: Ovarian follicles contain oocytes and support cells for oocyte development. Step 4: Therefore, choice C is correct as it accurately describes the structural aspect of the ovary. Summary: Choices A, B, and D are incorrect as they do not accurately describe the structural components of the ovary. Choice A talks about elastic tissue, choice B mentions glandular parenchyma, and choice D refers to blood vessels, none of which are specific to the structural arrangement of the ovary.