Human chorionic gonadotropin (hCG) produces fluid that activates sperm.

Correct Answer: D

Rationale: The correct answer is D: corpus luteum. Human chorionic gonadotropin (hCG) is produced by the developing placenta during pregnancy. This hormone helps maintain the corpus luteum, which in turn produces progesterone to support the pregnancy. The fluid produced by the corpus luteum helps activate sperm for fertilization. Choices A, B, and C are incorrect as they are not directly involved in the production of hCG or the activation of sperm.

Correct Answer: B

Rationale: The correct answer is B: spermatogenesis. Spermatogenesis is the process by which sperm cells are produced in the male testes. FSH (follicle-stimulating hormone) plays a crucial role in stimulating the production of sperm within the testes. During spermatogenesis, sperm cells go through various stages of development, including the formation of a head, midpiece, and tail. The other choices are incorrect because: A: Male testes are not and tail is called ________. This statement is incomplete and does not make sense in the context of the question. C: FSH functions solely in. This choice is incomplete and does not provide any relevant information about the process of sperm production. D: Acrosomal reaction. This term refers to a specific event that occurs during fertilization and is not directly related to the overall process of sperm production in the testes.

Correct Answer: C

Rationale: The correct answer is C: second. An embryo is known as a fetus during parturition by the second week of pregnancy. This is because by the end of the eighth week of gestation, the embryo has developed all major organs and structures, transitioning to the fetal stage. Choice A is incorrect because oxytocin increases during labor, not by the second week of pregnancy. Choice B is incorrect as the first contractions of the uterus occur during labor, not during the second week of pregnancy. Choice D is incorrect as oxytocin actually promotes uterine contractions during labor.

Correct Answer: D

Rationale: The correct answer is D because the primary oocyte completes its first meiotic division just before fertilization. This occurs when the oocyte is released from the ovary during ovulation. The meiotic division is completed when the sperm penetrates the oocyte, forming a zygote. Choices A, B, and C are incorrect because the primary oocyte does not complete its first meiotic division during fetal development, just after ovulation, or just before ovulation.

Correct Answer: D

Rationale: Rationale: 1. Leydig cells are located in the testes and are responsible for secreting testosterone. 2. Testosterone is a male sex hormone crucial for the development of male reproductive tissues. 3. Spermatocytes and oocytes are involved in gamete production, not testosterone secretion. 4. Anterior pituitary cells secrete hormones like FSH and LH, not testosterone. Summary: Leydig cells secrete testosterone in the testes, making them the correct choice. Spermatocytes, oocytes, and anterior pituitary cells are not involved in testosterone secretion.