Protein found in a biological system with a unique three-dimensional structure and biological activity is called a native protein. When a protein in its native form is subjected to a physical change like a change in temperature or a chemical change like a change in $pH$,denaturation of proteins takes place. Explain the cause.

(N/A) When a protein in its native form is subjected to physical changes (like change in temperature) or chemical changes (like change in $pH$),the hydrogen bonds are disturbed. Due to this,the globules unfold and the helix gets uncoiled. As a result,the protein loses its biological activity. This process is known as the denaturation of proteins.