Question

contains a heterocyclic ring

Answer 1

Heterocyclics are cyclic organic compounds that contain a heteroatom (Nitrogen, Sulfur, Phosphorus, Oxygen, etc.). For example, pyridine:

Heterocyclic compounds very often form part of more complex molecules, as well as various macromolecules (biopolymers), for example, cyanocobalamin (vitamin B12), DNA, RNA, etc.