Question

The exchange of gases between the air and blood takes place across the walls of the __________.

Answer 1

Breathing:

1. The process, by which air is drawn in from the atmosphere into the lungs and forced out from the lungs back into the atmosphere is known as breathing.
2. Alveoli are the tiny air sacs present in the lungs where the main exchange of gases takes place.
3. The walls of the alveolus are very thin, so the molecules of gases can easily pass through it.
4. Along with this, each alveolus has a very complex, thin blood capillary network through which gases can come in and out.
5. Thus, oxygen diffuses into the blood from the alveoli and carbon diffuses out from the blood capillaries into the alveolus.

Final answer:
The exchange of gases between the air and blood takes place across the walls of the alveoli.