A person has 400 million alveoli per lung with an average radius of 0.1 mm for each alveolus. Considering the alveoli are spherical in shape, the total respiratory surface of that person is closest to
(A) 500 mm2
(B) 200 mm2
(C) 100 mm2
(D) 1000 mm2
Correct option (D) 1000 mm2
Explanation:
