Which of the following is/are an example(s) of asexual reproduction?

Correct Answer: D

Rationale: The correct answer is D: All of the above. Asexual reproduction involves the production of offspring from a single parent without the involvement of gametes or fertilization. - Fission: Organism splits into two or more parts, each regenerating into a new individual. - Fragmentation: Parent organism breaks into fragments, with each fragment developing into a new individual. - Budding: New individuals develop as outgrowths or buds from the parent organism. All these processes result in genetically identical offspring, making them examples of asexual reproduction.

Correct Answer: C

Rationale: The correct answer is C because the luminal epithelium of efferent ductules is indeed irregular, which helps in absorption and modification of fluid. A, Leydig cells are located outside the seminiferous tubule. B, Sertoli cells provide nourishment and support to developing sperm cells but do not mature spermatids. D, Contraction of smooth muscle in vas deferens is stimulated by the parasympathetic nervous system, not the sympathetic.

Correct Answer: A

Rationale: The correct answer is A: Seminoma is the commonest pure testicular germ cell tumor. Seminoma is indeed the most common pure germ cell tumor of the testis, accounting for about 40-50% of cases. It typically presents in young adult males and has a good prognosis. Seminoma histologically consists of clear cytoplasmic glycogen and distinct cell borders. Choice B is incorrect as it seems to be incomplete. Choice C is incorrect as AFP (alpha-fetoprotein) increases in yolk sac tumors, not choriocarcinoma. Choice D is incorrect as Schiller-Duvall bodies are characteristic of embryonal carcinoma, not yolk sac tumors.

Correct Answer: C

Rationale: The testes originate in the abdominal cavity in a fetus. During development, they descend into the scrotal sac through the inguinal canal. This process is essential for proper sperm production as the scrotal environment provides optimal temperature for sperm development. The other choices are incorrect because the testes do not initially form in the scrotal sac, pelvic cavity, or retroperitoneal space. The correct sequence of descent from the abdominal cavity to the scrotal sac is crucial for normal reproductive function.

Correct Answer: D

Rationale: The correct answer is D because a low sperm count (less than 20 million per ml semen) can lead to infertility as it decreases the chances of successful fertilization. A high sperm count (choice A) is actually beneficial for fertility. Increased acrosomal activity (choice B) can enhance fertilization potential. Normal morphology (choice C) refers to the shape and size of sperm, which is important for fertility but not the primary factor in infertility due to low sperm count. Overall, a low sperm count is the most significant factor in infertility.