62. Birds and mammals both have negative pressure breathing, but birds are more efficient because of which of the following
reasons?
(A) The bird's mouth movements are able to force air into the lungs.
(B) The tidal volume in birds is much larger than in a comparably sized mammal.
(C) The flow of air in a bird's lungs is from posterior to anterior.
(D) The brain of the bird maximizes oxygen uptake more efficiently.
(E) The maximum PO2 is significantly higher in bird lungs.