That is, unlike the carbon-only ring like in benzene and napthalene, there are other elements in the backbone, such as in pyrimidine and purine.
... The racial makeup of the town is 95.82% White, 0.50% African American, 0.04% Native American, 1.49% Asian, 0.00% Pacific Islander, 1.08% from other races, and 1.08% ...