Amino acids are classified as acidic, basic, or neutral depending upon the relative number of amino and carboxyl acid groups in their molecule. Which among the following are acidic?

How many amino acids have a $-{\mathrm{CH}}_3$ group in its side chain?

Some amino acids are listed below:
$\mathrm{Tyr}, \mathrm{Cys}, \mathrm{Glu}, \mathrm{Leu}, \mathrm{Phe}$

How many of the following amino acids having an aromatic ring in their structures?

Which of the following pairs of the compound are epimers?

$\left(\mathrm{a}\right)$ Glucose and mannose

$\left(\mathrm{b}\right)$ Mannose and galactose

$\left(\mathrm{c}\right)$ Glucose and galactose

$\left(\mathrm{d}\right)$ Mannitol and sorbitol