Question

༒How can the heart be strong enough to pump blood up your legs against gravity?☆༻☆༻☆༻☆༻​

Answer 1

Answer:

The valves close when blood starts to flow in one direction , so the blood in veins can flow in the direction back to the heart , which is up the lungs ... so it is combination of blood pressure from the heart's pumping action , the valves and muscle movement that get the blood up the legs against gravity .