AP BIOLOGY

Detailed explanation-1: -Oxygen-rich blood flows from the lungs back into the left atrium (LA), or the left upper chamber of the heart, through four pulmonary veins. Oxygen-rich blood then flows through the mitral valve (MV) into the left ventricle (LV), or the left lower chamber.

Detailed explanation-2: -Correct answer: In the cardiopulmonary system blood flows from the right atrium to the right ventricle, then through the pulmonary artery, lungs, and pulmonary vein, before re-entering the heart at the left atrium.

Detailed explanation-3: -Your pulmonary veins are the only veins in your body that carry oxygen-rich blood. All your other veins carry oxygen-poor blood. Similarly, your pulmonary arteries are the only arteries that carry oxygen-poor blood. All the rest of your arteries carry oxygen-rich blood.

Detailed explanation-4: -From lungs, oxygenated blood enters left atrium to go to left ventricle to be carried by aorta to whole body. So, the correct answer is ‘Right atrium