Which hormone is the major contributor to the development of secondary sexual characteristics in females?

Correct Answer: C

Rationale: The correct answer is C: Estrogen. Estrogen is the major hormone responsible for the development of secondary sexual characteristics in females. It promotes breast development, regulates the menstrual cycle, and influences body fat distribution. Progesterone (A) is involved in preparing the uterus for pregnancy. Testosterone (B) is the primary male sex hormone, but it also plays a role in female secondary sexual characteristics. Prolactin (D) is primarily responsible for milk production in females, not the development of secondary sexual characteristics.

Correct Answer: C

Rationale: The corpus luteum is a temporary endocrine structure formed in the ovary after ovulation. It functions to produce both estrogen and progesterone. Estrogen helps in the growth and development of the endometrial lining, while progesterone maintains the uterine lining for potential implantation of a fertilized egg. The other choices are incorrect because the corpus luteum does not solely produce estrogen (choice A) or progesterone (choice B). Additionally, it does not produce hCG (choice D), which is mainly produced by the placenta during pregnancy.

Correct Answer: A

Rationale: Testosterone is the correct answer because it is the primary male sex hormone responsible for the development of male secondary sexual characteristics such as facial hair, deep voice, and muscle growth. Testosterone is produced by the testes in males. Progesterone (B) is a female sex hormone involved in the menstrual cycle and pregnancy. Estrogen (C) is the primary female sex hormone responsible for the development of female secondary sexual characteristics. FSH (D) is a hormone that stimulates the production of sperm in males and the maturation of eggs in females, but it is not directly responsible for male secondary sexual characteristics.

Correct Answer: D

Rationale: The correct answer is D: hCG. Human Chorionic Gonadotropin (hCG) is produced by the placenta after implantation, confirming pregnancy. Estrogen (A) and Progesterone (C) are important hormones in pregnancy but do not specifically confirm it. FSH (B) is Follicle-Stimulating Hormone, which is not directly related to pregnancy confirmation. hCG is the most reliable indicator of pregnancy as its levels rise significantly in early pregnancy, making it the correct choice.

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.