試題詳解

42. Which of the following statements concerning animal reproduction is correct?
(A) Animals reproduce exclusively by sexual reproduction.
(B) In humans, female ovarian cycles are controlled by the blood concentration of follicle-stimulating hormone (FSH) and luteal hormone (LH).
(C) In humans, LH and FSH are absent in males.
(D) In humans, maternal blood vessels are directly connected to fetal blood vessels in the placenta.