 "process paragraph : : You breathe air in. Air enters bronchial tubes. Air is then split into the bronchioles of each lung. Bronchioles have alveoli which are tiny air sacs. Alveoli is surrounded by many small blood vessels. Oxygen passes through alveoli into blood vessels. Blood leaves the lungs as it travels through the body. Blood carries carbon dioxide back to the lungs. Carbon dioxide released when you exhale. ", "event : Air enters bronchial tubes.", "entity : air" 
 known location 