What hormone is produced by the placenta to maintain early pregnancy?

Correct Answer: D

Rationale: The correct answer is D: hCG (human chorionic gonadotropin). hCG is produced by the placenta to maintain early pregnancy by supporting the corpus luteum, which in turn produces progesterone necessary for maintaining the uterine lining. Prolactin is responsible for milk production, not maintaining pregnancy. Estrogen plays a role in the menstrual cycle but is not the primary hormone for early pregnancy maintenance. Progesterone is crucial for pregnancy but is supported by hCG in the early stages.

Correct Answer: B

Rationale: The correct answer is B: The vagina transports sperm from the cervix to the uterus. This is because the vagina serves as the passageway for sperm to travel from the cervix through the uterus and into the fallopian tubes to fertilize the egg. The other choices are incorrect because: A) Fertilization typically occurs in the fallopian tubes, not the vagina. C) Estrogen is primarily produced by the ovaries, not the vagina. D) Sperm is not stored in the vagina after ejaculation, as it quickly travels through the cervix to reach the uterus.

Correct Answer: B

Rationale: Estrogen is the correct answer as it stimulates the growth of the uterine lining during the proliferative phase of the menstrual cycle. It is produced by the developing ovarian follicles. Progesterone maintains the uterine lining in the second half of the cycle. FSH and LH are involved in follicle development and ovulation, respectively, but they do not directly stimulate uterine lining growth.

Correct Answer: D

Rationale: The correct answer is D: Fallopian tube. The rationale is as follows: Sperm meets the egg in the fallopian tube during fertilization. The fallopian tube provides the ideal environment for fertilization to occur due to its structure and cilia movement that help transport the egg and sperm. The other options are incorrect because: A: Ovary is where the egg is produced but not where fertilization occurs. B: Cervix is the lower part of the uterus and allows passage of sperm into the uterus but not the site of fertilization. C: Uterus is where the fertilized egg implants and develops into a fetus, but not where fertilization occurs.

Correct Answer: C

Rationale: The cervix during pregnancy functions to prevent bacterial infection by forming a barrier between the uterus and the outside environment. This is crucial to protect the developing fetus from harmful bacteria. The other choices are incorrect because the cervix does not directly support fetal development, secrete estrogen, or store sperm during pregnancy.