In alveoli of the lungs, the air at the site of gas exchange, is separated from the blood by
A. alveolar epithelium only
B. alveolar epithelium and capillary endothelium
C. alveolar epithelium, capillary endothelium and tunica adventitia
D. alveolar epithelium, capillary endothelium, a thin layer of tunica media and tunica adventitia
Answer:B
In alveoli of the lungs, the air at the site of gas exchange, is separated from the blood by
A. alveolar epithelium only B. alveolar epithelium and capillary endothelium C. alveolar epithelium, capillary endothelium and tunica adventitia D. alveolar epithelium, capillary endothelium, a thin layer of tunica media and tunica adventitia