Identify the fibrous protein from the following.

$A$ short peptide on complete hydrolysis produces $3$ moles of glycine $(G)$,$2$ moles of leucine $(L)$ and $2$ moles of valine $(V)$ per mole of peptide. The number of peptide linkages in it are $..............$.

The helical structure of proteins is stabilized by

$HC\equiv CH$ $\xrightarrow[HgSO_4]{H_2SO_4} (A)$ $\xrightarrow[(1) NH_3 + HCN]{(2) H_3O^{\oplus}} (B);$ The product $(B)$ of the given reaction is:

How many subunits are present in hemoglobin?

Which among the following is a basic amino acid?