Answer:haemoglobin
Explanation:
Inside the air sacs, oxygen moves across paper-thin walls to tiny blood vessels called capillaries and into your blood. A protein called haemoglobin in the red blood cells then carries the oxygen around your body.
Alveoli are part of the reparation system found in the lungs. They are covered in capillaries. In Alveoli, oxygen diffuses from the air into the blood vessels surrounding the alveoli and carbon dioxide from the body diffuses from blood into the alveoli’s air spaces. Alveoli clump together and form sacs.
So he doesn't fall and drown
