Question

this grapelike out - pouching lined with epithelium and supported by a thin, elastic basement membrane is the site where gas exchange occurs in the lungs. lobule alveolus bronchiole trachea

Explanation:

Alveoli are grapelike out - pouchings in the lungs lined with epithelium and supported by a thin, elastic basement membrane where gas exchange occurs. Lobules are larger structural units in the lungs. Bronchioles are air - conducting passages. The trachea is the windpipe.

Answer:

B. Alveolus