2. Inside the body proteins will fold into a three dimensional structure that may depen a) hydrophobic side chains of amino acids associating with each other b) ionic interactions of charged side chains c) polar side chains associating with surrounding water molecules.T d) All the above (a, b and c) are correct.

12.The 3 dimensional structure is the structure when the folding of the polypeptide chain results in the formation of a biologically active protein. Various molecular interactions are required to keep the folded structure together. 

During the process of translation, the protein is formed in the form of a linear chain of amino acids or a random coil. This structure is not called as a stable 3 dimensional structure. The interaction of the amino acids in the chain forms a defined and folded structure. Thus the 3 dimensional structure of protein is determined by the sequence of amino acids driving the folding and intra molecular bonding.