Why do scientists study proteins to find evidence for evolution?

Protein sequences never change, so scientists study proteins to discover how species of organisms evolve.
Proteins reflect DNA sequences, so scientists study proteins to look for genetic similarities and differences in organisms.
A lack or presence of proteins in an organism's body indicates whether the organism lives on land or in water.

Question

Why do scientists study proteins to find evidence for evolution?

Protein sequences never change, so scientists study proteins to discover how species of organisms evolve.
  		Proteins reflect DNA sequences, so scientists study proteins to look for genetic similarities and differences in organisms.
  		A lack or presence of proteins in an organism's body indicates whether the organism lives on land or in water.

rina.r · Answer

WELCOME TO SO(;
Its B Proteins reflect DNA sequences, so scientists study proteins to look for genetic similarities and differences in organisms.