I think it is c because primary research is original and from the certain time while secondary research is collected from others by research and stuff
Answer:
A. . Blood from the veins enters the ventricles.
C. Atria push blood into the ventricles
Explanation:
Blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. As the atrium contracts, blood flows from your right atrium into your right ventricle through the open tricuspid valve.
1. The right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle through the tricuspid valve.
2.The right ventricle pumps the oxygen-poor blood to the lungs through the pulmonary valve.
3. The left atrium receives oxygen-rich blood from the lungs and pumps it to the left ventricle through the mitral valve.
4. The left ventricle pumps the oxygen-rich blood through the aortic valve out to the rest of the body.
Answer:
i dont know but if you look it up some more you should get it
Explanation:
