Early biologists referred to animals as "simple" and "advanced," but now it is more accurate to use the following terms:
A. "generalists" and "specialists", since this is how biologists classify characters.
B. "evolved" and "un-evolved", since everything ties together with evolution.
C. "primitive" and "derived", since some early forms became very complex and some evolved forms are derived from them but lost characters and are simple.
D. "simple" and "complex", since anatomy terms are more exact.
E. "allopatric" and "sympatric", since the species is most important.