The complementarity-determining regions are-: (A) Restricted to light chains, (B) Are in the constant pa of the Ig molecule, (C) Binds to Fc receptor, (D) Are concerned in antigen recognition
Answer is D. In the variable region of the H and L domains, maximum sequence variation is concentrated in a few discrete regions called hyperevariable regions ( HV) . HV regions form the antigen binding site of the antibody molecule which is complementary to the structure of the epitope and are called Complementary Determining Regions (CDRs)