ANSWER IS : A troposphere
Answer:
UGAG is this what u were looking for... if not sucks for you lol
Explanation:
A. moisten is the best answer u got
Answer:
Moist walls - gases dissolve in the moisture helping them to pass across the gas exchange surface. 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.
