Answer:the atrioventricular (AV) valves prevent counterflow of blood added into the atria during ventricular contraction.
Step-by-step explanation:
Aortic and pulmonary semilunar valves control the flow of blood into the heart. The correct answer option is 'the atrioventricular (AV) valves prevent counterflow of blood added into the atria during ventricular contraction. ' AV valves separate the atrium from the ventricle.