Which of the following bond is preserved during denaturation of proteins?

Primary structure, such as the sequence of amino acids held together by covalent peptide bonds, is not disrupted by denaturation. When a protein is denatured, secondary and teiary structures are altered but the peptide bonds of the primary structure between the amino acids are left intact. Since all structural levels of the protein determine its function, the protein can no longer perform its function once it has been denatured. This is in contrast to intrinsically unstructured proteins, which are unfolded in their native state, but still functionally active. Ref satyanarayana 4e