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.
... 37.6 km² (14.5 mi²) of it is land and 4.1 km² (1.6 mi²) of it is water. The total area is 9.81% water. Demographics As of the census of 2000, ...