Blood returining from the body (system circualtion) first enters which chamber of the heart?
a. left atrium
b. right atrium
c. left ventricle
d. rigth ventricle

B

Explanation:Blood enters the right atrium and passes through the right ventricle. The right ventricle pumps the blood to the lungs where it becomes oxygenated. The oxygenated blood is brought back to the heart by the pulmonary veins which enter the left atrium. From the left atrium blood flows into the left ventricle.

i-i-i-i-i-i don't k-k-k-k-know.

when you rub, you also apply pressure, that pressure can urge the poop to come out. i think that when your rubbing, you also might be slightly breaking it up and that can further fill the stomach.