Answer: alveoli
Explanation:
The exchange of gases from the air and the blood occur in the alveoli tubes. These are tiny tubes where the oxygenated air diffuse inside the lungs from the respiratory tract and the oxygen is added up to the blood and the carbon dioxide is expelled out by following the same root. This way the deoxygenated blood get purified with the oxygenated blood.
On the basis of the above explanation,The __alveoli________ are tissues where gases from the air and the blood are exchanged.