Answer:
Increasing or decreasing pH does not affect primary structure.
Explanation:
Proteins may be defined as the polymers of the amino acids and are bonded together through the peptide bond. The proteins folding includes the primary structure, secondary, tertiary structure and Quaternary structure.
The complete denaturation of the primary structure of protein results in the permanent loss of the biological activity. The physical conditions like temperature, pH affects the primary structure of proteins. The high or low pH may results in the loss or gains of the ions and affects the primary structure of protein.
Thus, the correct answer is option (C).