Chromosomes females have xx and males are xy
The monomer units of the carbohydrates vary in their total numbers extensively. Moreover, positions of the carbonyl groups along with the orientation of the hydroxyl groups also vary in the carbohydrates' monomers. The presence of any modification is also variable.
On the other hand, the nucleic acids have only 4 monomeric units. The linkages between the nucleic acid residues have less geometry than the glycosidic linkages.
Commensalism. The fish is benefited and the sea urchin is not affected.
