Question

what is the purpose of heart valves?
to regulate blood pressure
to control blood flow
to produce red blood cells
to transport oxygen in the blood
to filter waste products from the blood

Explanation:

Heart valves open and close to ensure blood flows in one direction through the heart chambers and blood vessels. For example, the mitral valve allows blood to flow from the left atrium to the left ventricle and prevents back - flow.

Answer:

B. To control blood flow