When a protein is denatured by chemical, heat or other substances, the primary structure remains intact. Hence, the correct answer would be the tertiary structure.
Denaturation of proteins generally causes the breakage of weak bonds on which the folding and the entire protein structure is built. When this happens:
- the peptide bonds between the component amino acids remain intact. Hence, the primary structure is conserved
- the destruction of other bonds means that the secondary and tertiary structures are affected.
Agents that are capable of denaturing proteins include high temperature, changes in acidity/basicity, UV radiation, high concentration of salts, and so on.
The correct answer as to which would be affected when a protein is denatured in this case would, therefore, be the tertiary structure.
More on protein denaturation can be found here: https://brainly.com/question/15241721
