Can an enzyme be called a polymer?

The condensation polymer among the following is

In the given pentapeptide, find out an essential amino acid $(Y)$ and the sequence present in the pentapeptide: Choose the correct answer from the options given below:

What is the correct order of acidity for the positions $(X)$,$(Y)$,and $(Z)$ in the given compound?

Assertion $(A)$: The denaturation of proteins can destroy all $1^{\circ}, 2^{\circ}$ and $3^{\circ}$ protein structures.
Reason $(R)$: Curdling of milk is due to denaturation of proteins.
The correct option among the following is

Proteins when heated with conc. $HNO_3$ give a yellow colour. This is