They are called alveoli.
emphysema
Emphysema
Emphysema or Pulmonay emphysema
Emphysema is a condition where there are little holes in the air sacs in the lungs. It is usually caused by excessive smoking.
In healthy individuals, alveoli are hollow plump air sacs where gas exchange occurs. They look like an upside down grapes on a stem. In emphysema, the alveoli become flattened or collapse.
emphysema emphysema
emphysema
Alveoli are the tiny air sacs that look like hollow plump grapes in healthy people. In emphysema, many of the alveoli collapse so there is less surface area for gas exchange.
Emphysema is a lung condition in which tiny air sacs in the lungs - alveoli - fill up with air. As the air continues to build up in these sacs, they expand, and may break or become damaged and form scar tissue.
If by "broken" you mean not able to exchange air (CO2 and Oxygen), then the likely answer is Emphysema. The air sacs (called aveoli) are elastic-like and they inflate and collapse completely in a healthy lung. With Emphysema, they gradually lose more and more of this elasticity, and remain partly open all the time. This causes them to retain CO2 -carbon-dioxide, and therefore- allow less oxygen to be brought into the body.
Emphysema is a disease that destroys the tiny air sacs in your lungs. In this case it can even cause lung cancer. A person with advanced emphysema uses 80% of his/her energy to breathe.
air sacs Hope I helped! Ace that test :P