Koilonychias is a specific feature of

Correct Answer: D

Rationale: Koilonychias (spoon-shaped nails) is a classic sign of iron deficiency anemia (D) due to impaired hemoglobin synthesis affecting nail growth. Hemolytic anemia (A), sickle cell disease (B), and thalassemia major (C) cause RBC destruction or abnormal hemoglobin, not koilonychias. B12 deficiency (E) causes neurologic symptoms, not nail changes—iron deficiency is specific.

Correct Answer: C

Rationale: Spermatogenesis, the process of sperm cell production, is a primary role of the testicle, occurring in the seminiferous tubules. Option A incorrectly ties endocrine function to sperm production (which is exocrine), B reverses the gland functions, and D is inaccurate as semen is a composite fluid produced by multiple glands, not just the testicle.

Correct Answer: D

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: B

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: D

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.