Question

what is occurring during isovolumetric contraction?
o the amount of blood in each atria is the same
the semilunar valves are open and the av valves are closed
o the point at which all blood has been ejected from the ventricles
o all four valves are closed
o both atria are ejecting blood at the same time

Explanation:

During isovolumetric contraction, all four heart valves (AV and semilunar) are closed as ventricular pressure rises without volume change.

Answer:

all four valves are closed