In humans, oxygen and carbon dioxide are exchanged in the blood within many small sacs called alveoli in the lungs. Alveoli provide a large surface area for gas exchange. Recent careful measurements show that the total number of alveoli in a typical pair of lungs is about 480 x 106 and that the average volume of a single alveolus is 4.2 x 10 um. (The volume of a sphere is V =Tr, and the area of a sphere is A = 4rr?.) 4 3 3 %D Part A If we assume that alveoli are spherical, what is the diameter of a typical alveolus? 0.20 mm O 2 mm 20 mm O 200 mm Submit Request Answer