Answer:Plate tectonics explains why Earth's continents are moving; the theory of continental drift did not provide an explanation. Therefore, the theory of plate tectonics is more complete. It has gained widespread acceptance among scientists
Explanation:
The cycle runs like this:
Deoxygenated blood enters from the body to the heart via the superior/inferior vena cava. It goes directly to the right atrium and down to the right ventricle. From there it'll pass through the pulmonary artery into the lungs where diffusion will happen in the capillaries. Gas exchanges will occur and the blood will become oxygenated and return to the heart via the pulmonary vein. From the pulmonary vein it will enter back into the left atrium and then will give the final pump of oxygen rich blood into the aorta and then into the entire body.
The tricuspid valve shuts. This prevents blood from flowing backward into the right atrium while the ventricle contracts. So, your answer will be the Tricuslid Valve. Hope I helped!
