6. A monoclonal antibody differs from a polyclonal antibody in that monoclonal antibodies:
(A) are labeled with chemicals that can be visualized.
(B) are produced by cells from the same organism that produced the antigen.
(C) are synthesized by a population of identical, or "cloned," cells.
(D) are synthesized only in living organisms.
(E) have only a single polypeptide chain that can recognize an antigen.