The correct pathway for oxygen-poor blood is right atrium → right ventricle → pulmonary artery → lungs (first option).
Explanation:
Unoxygenated or oxygen-poor blood is that which comes from tissues that have exchanged O₂ for CO₂. The venous return is in charge of taking that blood to the heart and then to the lungs.
Oxygen-poor blood reaches the right atrium from the vena cava.From the atrium the blood passes to the right ventricle through the tricuspid valve.The right ventricle pumps the blood to the lungs through the pulmonary arteries, the only arteries that carry venous blood.
Once in the lungs, the blood exchanges CO₂ for O₂, returning to the heart through the pulmonary veins.
The other options are not correct because:
Left atrium, left ventricle, aorta, body corresponds to the flow of oxygenated blood that comes from the lungs and is pumped to the entire body.Left atrium, right atrium, left ventricle, right ventricle not correspond to the order in which blood flows through the heart.Right ventricle, right atrium, pulmonary veins, lungs not correspond to the flow of oxygen-poor blood.
