question: What are the little sacs at the end of the bronchioles called?
distractor3: ganglion
distractor1: lung
distractor2: respiratory sacs
correct_answer: alveoli
support: The bronchioles lead to the alveoli. Alveoli are the little sacs at the end of the bronchioles ( Figure below ). They look like little bunches of grapes. Oxygen is exchanged for carbon dioxide in the alveoli. That means oxygen enters the blood, and carbon dioxide moves out of the blood. The gases are exchanged between the blood and alveoli by simple diffusion.