The hormone testosterone is tubes called seminiferous tubules that produced by the ________ cells of the are found within each ________. testes.

Correct Answer: B

Rationale: The correct answer is B: spermatogonia. Spermatogonia are the cells within the seminiferous tubules of the testes that give rise to sperm cells. Testosterone is produced by Leydig cells, not spermatogonia. A is incorrect because the spermatic cord does not produce testosterone. C is incorrect as the testis is the overall organ where the seminiferous tubules are located. D is incorrect as oogonia are female germ cells found in the ovaries, not the testes.

Correct Answer: C

Rationale: The correct answer is C: blastocyst. At this stage of development, the embryo is a hollow ball of cells with an inner cell mass. This structure is called a blastocyst. A is incorrect because testosterone is a hormone, not a cell structure. B is incorrect as it does not describe the early stage of embryonic development. D is incorrect as luteinizing hormone is a hormone involved in the menstrual cycle, not embryonic development.

Correct Answer: D

Rationale: Step-by-step rationale: 1. Testosterone inhibits the release of luteinizing hormone (LH) through negative feedback. 2. LH is produced by the anterior pituitary. 3. Therefore, testosterone exerts negative feedback on the anterior pituitary to turn off LH secretion. 4. This maintains hormonal balance in the body. Summary of other choices: A. Incorrect because testosterone primarily affects LH secretion, not follicle stimulating hormone (FSH). B. Incorrect as it inaccurately suggests that testosterone turns off both LH and FSH secretion. C. Incorrect because Sertoli cells are involved in spermatogenesis, not LH regulation.

Correct Answer: C

Rationale: The correct answer is C: 400,000,000. During ejaculation, a healthy male typically releases around 200-500 million sperm cells. Choice A (4,000) and B (40,000) are too low compared to the average sperm count. Choice D (4,000,000) is also significantly lower than the typical sperm count, making it incorrect. Therefore, C is the correct answer as it aligns with the standard range of sperm count during ejaculation.

Correct Answer: B

Rationale: The correct answer is B: Cervix. The cervix is the narrow passage that connects the uterus to the vagina. It acts as a barrier between the uterus and the outside environment. The other choices are incorrect because: A: Vagina is the birth canal and does not directly connect the ovary to the uterus. C: Fallopian tube connects the ovary to the uterus but does not directly attach to it. D: Perineorrhaphy is a surgical procedure to repair the perineum and is not related to connecting the ovary to the uterus.