Question

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

Explanation:

Alveoli are tiny air - sacs in the lungs. They have a large surface area and thin walls. Oxygen diffuses into the blood from alveoli, and carbon dioxide diffuses out of the blood into alveoli. Lungs are the organ that contains alveoli but the primary site for gas exchange is the alveoli. Trachea is a windpipe for air passage. Bronchioles are small airways. Bronchi are larger airways that branch from the trachea. None of these (trachea, bronchioles, bronchi) have the structure suitable for efficient gas exchange like alveoli.

Answer:

Alveoli