Question

lo 4.2. what is the primary site for gas exchange?
lungs
alveoli
bronchioles
trachea
bronchi

Explanation:

The alveoli are tiny air - sacs in the lungs. They have a large surface area and thin walls. Oxygen diffuses from the alveoli into the blood, and carbon dioxide diffuses from the blood into the alveoli. Lungs are the organ that contains the alveoli. Bronchioles are small airways that lead to the alveoli. Trachea is the windpipe that conducts air to the bronchi. Bronchi are the main passageways into the lungs. But the actual site of gas exchange is the alveoli.

Answer:

Alveoli