One Reason the Field of Proteomics Is Continually Evolving Following

One reason the field of proteomics is continually evolving following the systematic study of an organism's genome is because

A) it became apparent that while the organism's genome is relatively stable, protein expression in an organism is constantly changing.
B) the expression of proteins is fixed in each organism so sequencing the genome is essential to understanding phenotypes.
C) it became apparent that protein expression is relatively uniform, whereas the genome is constantly changing.
D) once the genome had been sequenced, all protein expression was understood.