Some Species, Like Camels, Alpacas, and Llamas, Have Evolved Variant

Multiple Choice

Some species, like camels, alpacas, and llamas, have evolved variant forms of immunoglobulin proteins that retain the ability to bind to antigens. While overall the antibodies made by these animals are simpler than human or mouse antibodies, an important feature conserved among all of these antibodies is:

A) The presence of both heavy and light chain polypeptides
B) Antigen-binding sites comprised of V_H and V_L sequences
C) The presence of exactly three constant region domains
D) The presence of two antigen-binding sites per antibody
E) The presence of multiple disulfide bonds linking antibody light chains to heavy chains