What is the alveolar-capillary membrane? the layer of cells through which gases are exchanged
the layer of cilia that traps debris from entering lungs
the pathway to the lungs from the trachea
a pulmonary artery that exchanges gases

A

Explanation: The blood–air barrier (alveolar–capillary barrier or membrane) exists in the gas exchanging region of the lungs. It exists to prevent air bubbles from forming in the blood, and from blood entering the alveoli. ... The barrier is permeable to molecular oxygen, carbon dioxide, carbon monoxide and many other gases.

can you plz give me the following

answer(d) call 911;