Oxygen (O2) and Carbon dioxide(CO2) are transported in humans through the bloodstream.
Oxygen is carried to the cells, whereas carbon dioxide is carried away from the cells.
The exchange of gases in the alveoli of the lungs and the surrounding blood capillaries. Oxygen is absorbed by the blood capillaries from the lungs’( oxyhaemoglobin ) alveoli by diffusion, while carbon dioxide is absorbed by the lungs’ alveoli from the blood capillaries by diffusion.