About percent of the total cardiac output goes to the kidney:

Correct Answer: C

Rationale: The kidneys receive ~25% (C) of cardiac output (~1.2 L/min of 5 L/min) for filtration. A, B are too low, D too high.

Correct Answer: C

Rationale: Resting cardiac output is ~5.25 L/min (C, 70 ml × 75 bpm). A and B are too low, D too high for rest.

Correct Answer: C

Rationale: S₂ (C) has a longer, sharper sound (~0.08 s) than S₁ (~0.07 s) due to semilunar valve closure. A is S₁, B is true but not unique, D is secondary.

Correct Answer: A

Rationale: Coronary arteries (A) supply oxygenated blood to the myocardium. Coronary veins (B) and sinus (C) drain deoxygenated blood, pulmonary artery (D) carries deoxygenated blood to lungs.

Correct Answer: C

Rationale: Cardiac output (C) is total blood ejected per minute from both ventricles: left to aorta, right to pulmonary trunk (~5 L/min).