Redirected from Heterocyclic
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.
... 20.7% who are 65 years of age or older. The median age is 44 years. For every 100 females there are 93.5 males. For every 100 females age 18 and over, there are 92.2 ...