Studies of the Structure of Proteins Such as Cytochrome C

Studies of the structure of proteins such as cytochrome c and lysozyme in different species have shown that

A) the rate of evolution of particular proteins is often relatively constant over time.
B) many nucleotide substitutions result either in no change in the amino acid sequence of the protein or in a change to a functionally equivalent amino acid.
C) there are fewer differences in the amino acid sequences of proteins whose organismal sources were closely related than in those whose sources were distantly related.
D) functionally important regions of a protein can be discovered by identifying the regions with the most amino acid substitutions.
E) All of the above