Alveoli: Understanding the Tiny Air Sacs in Your Lungs

The answer is alveoli.

Alveoli are tiny sacs of tissue that line the lungs. They are where oxygen from the air we breathe is exchanged for carbon dioxide from our blood. There are millions of alveoli in each lung, and they have a total surface area of about 100 square meters. This enormous surface area allows for a rapid exchange of gases, which is essential for survival.