Give two ways the lungs are adapted for efficient gas exchange

Adaptations of the alveoli:

Thin walls - alveolar walls are one cell thick providing gases with a short diffusion distance. ... Permeable walls - allow gases to pass through. Extensive blood supply - ensuring oxygen rich blood is taken away from the lungs and carbon dioxide rich blood is taken to the lungs.

they deliver oxygen to the blood

i am positive it is c. condensing but i may be wrong