Thepassage is primarily concerned with（） A．contrasting ...
A．contrasting the role of domination and courtship in determining the evolution of bird plumage
B．illustrating the effectiveness of a particular approach to categorizing various evolutionary innovations
C．documenting the origins of a currently accepted scientific theory about food and courtship
D．proposing a new explanation for the evolutionary reasons behind the ornamentation of male bird plumage
E．showing that physical adaptation plays an integral role in contributing to species identification of birds
