In haemoglobin,which amino acid acts as a blood buffer?

Which one of the following amino acids is an essential part of the human diet?

$S$ - Statement: Proteins are called conjugated proteins when they are associated with substances other than amino acids.
$R$ - Reason: Chlorophyll is essential for photosynthesis.

Match the following columns:

Column-$I$ (Amino Acid)	Column-$II$ (Example)
$P$. Acidic	$I$. Lysine
$Q$. Basic	$II$. Valine
$R$. Neutral	$III$. Glutamate

Which one is the most abundant protein in the animal world?

Which protein is found in the greatest abundance in the animal kingdom?