The main forces that stabilize the 2o and 3o structures of a protein are.               (A) Hydrogen bonds                      (B) Bisulphide linkages                   (C) Vanderwaals forces                (D) Electrostatic forces

2o structure is mainly stabilized by H–bonding. Overall folding of 2o structure represents 3o structure.Thus  20 and 30 structures are stabilized by                    1) Bisulphide linkages (S – S)                2) Vanderwaals forces (between alkyl groups)                3) Electrostatic forces  (between -COO– and -NH3+ )                4) H-bonds between -CO- and -NH- gps