Which of These Is a Proper Contrast Between Birds and Mammals

Multiple Choice

Which of these is a proper contrast between birds and mammals?

A) Birds are cold-blooded; mammals are warm-blooded.
B) Birds are egg laying; no mammals lay eggs.
C) Birds have air sacs in addition to lungs; mammals have no air sacs.
D) Birds lack a septum between the ventricles; mammals have a septum between the ventricles.
E) Birds,unlike mammals,require no parental care.