What happens to the biological activity of a protein due to denaturation?

Which of the following amino acids contains an imidazole ring?

Which of the following gives a positive test with ninhydrin?

The correct statements are:
$A$. Activation energy for enzyme catalysed hydrolysis of sucrose is lower than that of acid catalysed hydrolysis.
$B$. During denaturation,secondary and tertiary structures of a protein are destroyed but primary structure remains intact.
$C$. Nucleotides are joined together by phosphodiester linkage between $C_{3}$ and $C_{5}$ carbons of the pentose sugar.
$D$. Quaternary structure of proteins represents the spatial arrangement of two or more polypeptide chains.
Choose the correct answer from the options given below:

Identify the neutral amino acid from the following list represented by three-letter symbols.

Which among the following amino acids has the lowest molecular mass?