How does the human heart interact with gravity

Many parts of the cardiovascular system (including the heart) are influenced by gravity. On Earth, for example, the veins in our legs work against gravity to get blood back to the heart. Without gravity, however, the heart and blood vessels change – and the longer the flight, the more severe the changes.

i think the answer is g1

hope i

-lavira: )

this is a good question! i'll do some research and come back when i have the answer!