Question

the diagram represents blood vessels and alveoli (air sacs) in human lungs. how does an output from the circulatory system serve as an input to the respiratory system? a oxygen from the veins moves into the alveoli. b. carbon dioxide from the veins moves into the alveoli. c oxygen - rich blood moves from the veins into the alveoli. d. carbon dioxide - rich blood moves from the veins into the alveoli.

Explanation:

The circulatory system brings de - oxygenated blood (which is carbon - dioxide rich) to the lungs. In the lungs, at the alveoli, carbon dioxide diffuses from the blood in the veins into the alveoli to be exhaled out of the body. Oxygen from the inhaled air in the alveoli diffuses into the blood.

Answer:

B. Carbon dioxide from the veins moves into the alveoli.