What is the main function of the testes in males?

Correct Answer: B

Rationale: The main function of the testes in males is to produce sperm. Sperm production, known as spermatogenesis, occurs within the seminiferous tubules of the testes. Testosterone is primarily secreted by the Leydig cells in the testes, not the main function. Storing sperm is not a primary function, as sperm is continuously produced and released. Transporting sperm is mainly done by the vas deferens, not the testes themselves. Therefore, the correct answer is B, as it directly relates to the primary function of the testes in males.

Correct Answer: B

Rationale: The correct answer is B: Oxytocin. Oxytocin is the hormone responsible for stimulating the release of milk from the mammary glands. It acts by causing the contraction of the myoepithelial cells surrounding the alveoli in the breast, leading to the ejection of milk into the ducts. Estrogen (A) and FSH (D) are not directly involved in milk release. Prolactin (C) plays a role in milk production but not in the actual release of milk.

Correct Answer: B

Rationale: The correct answer is B: Oxytocin. Oxytocin is responsible for stimulating uterine contractions during labor. It is produced by the hypothalamus and released by the pituitary gland. Oxytocin acts on the smooth muscles of the uterus to initiate and regulate contractions, aiding in the progression of labor. Progesterone (A) helps maintain the uterine lining during pregnancy, while Prolactin (C) stimulates milk production. FSH (D) is a hormone that stimulates the growth and maturation of ovarian follicles in the ovaries.

Correct Answer: B

Rationale: The purpose of the zona pellucida during fertilization is to protect the egg during early development. It acts as a protective barrier around the egg, preventing polyspermy and providing structural support for the developing embryo. This choice is correct because the zona pellucida serves as a crucial protective layer for the egg in the initial stages post-fertilization. - A: Incorrect because the zona pellucida actually allows sperm entry into the egg. - C: Incorrect because the zona pellucida does not specifically facilitate sperm entry; its primary function is protection. - D: Incorrect because the zona pellucida is not directly involved in egg implantation, but rather in early embryonic development.

Correct Answer: B

Rationale: The correct answer is B: Capture the egg after ovulation. Rationale: 1. Fimbriae are finger-like projections at the end of the fallopian tube. 2. After ovulation, the fimbriae help in capturing the released egg from the ovary. 3. The captured egg is then transported to the fallopian tube for potential fertilization. Summary: A: Incorrect - Fimbriae do not transport the egg from the ovary to the uterus. C: Incorrect - Fimbriae do not support fertilization directly. D: Incorrect - Fimbriae do not release hormones.