Which describes gas exchange in the respiratory system?

The alveolar membrane- is where gas exchange between the blood and the atmosphere takes place. The gas molecules must diffuse across the alveolar epithelium and the capillary endothelium. ... Thus, the alveolar surface (as well as the respiratory bronchioles) have no cilia or mucus layer.

Explanation:

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the fossil record provides evidence of a common ancestor to many species.