C pass through capillaries
The right ventricle pump blood to the lungs. In the lungs the blood picks up Oxygen in the capillaries in the lungs. The Oxygen poor blood from the right ventricle goes into smaller and smaller arteries until it enters the capillaries in the lungs.
These capillaries turn into Oxygen rich veins. These blood flows into large and larger veins until the blood returns to the left Atrium. The left Atrium pumps the blood into the left Ventricle. The left Ventricle pumps the Oxygen rich blood into the Arteries that carry blood to the body cells.