2) Oxygen constantly diffuses from air or water into a animal's bloodstream. For this to happen, the concentration of oxygen in the blood must be A) greater than the concentration of oxygen in the air or water. B) greater than the concentration of carbon dioxide in the air or water. C) lower than the concentration of oxygen in the air of water. D) lower than the concentration of carbon dioxide in the air or water
The answer is C. For example when you inhale the air, oxygen diffuses from alveoli of lungs into the blood streams because it moves from high partial pressure in lungs to low partial pressure in blood streams.
