Question

14 which of the following helps return blood to the heart? multiple choice valves in the arteries positive pressure in thoracic cavity contracting skeletal muscles end systolic volume

Explanation:

Valves in arteries prevent back - flow of blood away from the heart, not towards it. Positive pressure in the thoracic cavity would impede blood return. End - systolic volume is related to the volume of blood in the heart at the end of systole, not blood return. Contracting skeletal muscles help squeeze veins and push blood back towards the heart through the action of the skeletal muscle pump.

Answer:

C. Contracting skeletal muscles