The correct answer is the respiratory system. The respiratory system is the organ system that helps get oxygen into your blood and removes carbon dioxide. The respiratory system includes the nose, pharynx, larynx, trachea, bronchi, and lungs. It is involved in gas exchange. Deoxygenated blood gets to the lungs via the pulmonary arteries, and carbon dioxide is removed from the blood, and oxygen diffuses into the blood during the gaseous exchange. The oxygenated blood leaves the lungs via pulmonary veins into the left atrium.
The respiratory system and the circulatory system work hand to hand to help get oxygen into the blood and removes carbon dioxide. The circulatory system consists of the heart, the arteries, veins, and capillaries. The circulatory system carries deoxygenated blood from the body to the lungs and carries oxygenated blood from the lungs to the rest of the body.