Which of the following amino acids is $NOT$ synthesized in our body?

Which of the following is the correct structure of $L$-alanine?

Identify the correct statement among the following $:$

Sanger's reagent is used for the identification of which of the following?

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

Identify the fibrous protein from the following.