What is the role of oxytocin during childbirth?

Correct Answer: B

Rationale: The correct answer is B: Stimulates uterine contractions. Oxytocin is a hormone released during childbirth that acts on the uterus to induce contractions, leading to the progression of labor. It plays a crucial role in facilitating the delivery of the baby. The other choices are incorrect because: A: Inhibiting uterine contractions would hinder the progress of labor. C: Oxytocin does not increase progesterone secretion; it primarily acts on the uterus. D: Oxytocin does not reduce fetal heart rate; instead, it helps in the expulsion of the baby by stimulating contractions.

Correct Answer: B

Rationale: Testosterone is the correct answer because it is the primary male sex hormone responsible for the development and maintenance of the male reproductive system, including the development of male sex organs like the testes and penis. Estrogen (A) is the primary female sex hormone, not responsible for male reproductive system development. Progesterone (C) is involved in the female reproductive system and pregnancy, not in male development. FSH (D) is a follicle-stimulating hormone that plays a role in both male and female reproductive systems but is not responsible for the development of the male reproductive system specifically.

Correct Answer: B

Rationale: The primary purpose of the placenta during pregnancy is to provide oxygen and nutrients to the fetus. The placenta acts as a bridge between the mother and the fetus, allowing for the exchange of oxygen, nutrients, and waste products. It filters oxygen and nutrients from the mother's blood to the fetus and removes waste products from the fetal blood to the mother's circulation. This process ensures the proper growth and development of the fetus. Choice A is incorrect because the placenta does not excrete waste products, it filters them. Choice C is incorrect as the placenta does not regulate the fetus's temperature. Choice D is incorrect because hCG (human chorionic gonadotropin) is a hormone produced by the embryo, not the placenta.

Correct Answer: C

Rationale: The correct answer is C because the main function of the female reproductive system is to provide a site for fertilization and support embryo development. This includes the production of eggs, the site for fertilization in the fallopian tubes, and the nurturing of the embryo in the uterus. Choices A and D are partially correct as the female reproductive system also produces hormones and regulates the menstrual cycle, but these are not the main functions. Choice B is incorrect as supporting fetal development occurs after fertilization and embryo development, which are the primary functions of the female reproductive system.

Correct Answer: B

Rationale: The correct answer is B: Secretes fluids that make up semen. The prostate gland secretes a milky fluid that makes up a significant portion of semen, aiding in sperm mobility and viability. This fluid also helps neutralize the acidic environment of the vagina, enhancing sperm survival. Option A is incorrect as the testes store sperm, not the prostate gland. Option C is incorrect as testosterone is primarily produced in the testes. Option D is incorrect as sperm production is regulated by the hypothalamus and pituitary gland, not the prostate gland.