Internal and external rotation of the humerus are made possible by a joint

Correct Answer: B

Rationale: The shoulder's ball-and-socket joint allows humeral rotation. 'Ball and socket,' is correct, the glenohumeral joint's structure, per anatomy (e.g., Tortora). 'Hinge,' (e.g., elbow) limits rotation. 'Condylar,' (e.g., knee) is less mobile. 'Saddle,' (e.g., thumb) is specific. Ball-and-socket's multidirectional range makes B the precise answer.

Correct Answer: B

Rationale: Sperm, the male reproductive cells, are produced in the seminiferous tubules of the testes. 'Seminiferous tubules,' is correct, per reproductive physiology texts like Tortora, where spermatogenesis occurs. 'Epididymis,' stores and matures sperm. 'Vas deferens,' transports sperm. 'Prostate gland,' produces seminal fluid. The tubules' role as the site of sperm cell formation distinguishes B as the accurate answer, foundational to male fertility.

Correct Answer: C

Rationale: Vitamin K is essential for synthesizing clotting factors (e.g., prothrombin) in the liver. 'Vitamin K,' is correct, per physiology texts like Guyton, preventing bleeding disorders. 'Vitamin A,' aids vision. 'Vitamin B,' encompasses metabolic coenzymes, not clotting. 'Vitamin D,' regulates calcium. Vitamin K's specific role in coagulation cascades makes C the accurate answer.

Correct Answer: C

Rationale: The urinary bladder holds about 600 ml at full capacity, though urge begins earlier. '600 ml,' is correct, per physiology texts like Guyton, varying (400-700 ml) by individual. '200 ml,' is minimal. '400 ml,' is functional but not maximum. '800 ml,' exceeds average. The 600 ml norm balances anatomy and function, making C the precise answer.

Correct Answer: D

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