Antibodies are composed of two types of peptides, heavy chains and light chains. One of the major classes of antibody molecules is immunoglobulin G (IgG). Two heavy chains and two light chains form one IgG molecule. Classify each statement as describing the heavy chains, light chains, or both chains of IgG. a. form the antigen-binding site b. are found in the Fab fragment c. are found in the FC fragment d. contain only one constant domain e. contain multiple variable domains f. contain multiple constant domains g. contain only one variable domain