Know anything about biology?

[schoolsux!]

Which of the following is the main reason why bird lungs are more efficient at extracting oxygen from air than the best mammalian lungs?
A) Air passes through the bird lung under pressure, "supercharging" the blood with oxygen.
B) Because of the air sac system, each breath of air passes through the bird lung twice.
C) The bird lung has no residual volume because it is composed of tiny tubes through which air passes in only one direction.
D) The bird lung has a higher surface area and capillary density than the lung of a mammal of the same size.
E) None of the choices are correct

Which of the following is not a function of hemoglobin?
A) binding to oxygen in the lungs
B) binding to carbon dioxide
C) binding to carbonic acid
D) unloading oxygen in active tissues
E) binding to hydrogen ions