The optically inactive amino acid is

Assertion : Proteins on hydrolysis produce amino acids.
Reason : Amino acids contain $-NH_2$ and $-COOH$ groups.

The pair in which both species have iron is

Assertion $(A)$: In aqueous solution,$\alpha$-amino acids exist as an internal salt called a zwitter ion.
Reason $(R)$: Proline is a natural amino acid having a secondary amino group. The correct option among the following is:

Proteins are $.......$.

$\alpha$-$helix$ is a secondary structure of proteins formed by twisting of polypeptide chain into right-handed screw-like structures. Which type of interactions are responsible for making the $\alpha$-$helix$ structure stable?