Amino acids that are not synthesized in the body are called ...... .

$A$ - In the solution of different $pH$,the structure of amino acids changes.
$R$ - It is because of the ionisable nature of $-NH_2$ and $-COOH$ groups.

Match the following.

Column-$I$	Column-$II$
$A$. Trypsin	$1$. Intercellular ground substance
$B$. $GLUT-4$	$2$. Hormone
$C$. Insulin	$3$. Enzyme
$D$. Collagen	$4$. Enables glucose transport into cells

Which of the following statements are correct regarding amino acids?
$A$. They are substituted methanes.
$B$. Serine is an aromatic amino acid.
$C$. Valine is a neutral amino acid.
$D$. Lysine is an acidic amino acid.
Choose the correct answer from the options given below:

Which is the most common source of protein for vegetarians in our country?

Valine is an amino acid of which type?