The main differences might be expected in the amino acid composition of X versus Y because the X polypeptide is made up of one smaller unit of amino acid while on the other hand, Y polypeptide is made up of four smaller units of amino acids. The name of X is monomer which means composed of one amino acids while Y exists as a tetramer which means it has four amino acids. So we can conclude that the main difference between X and Y is the presence of number of amino acids.
