Organic molecules refer to those that contain hydrogen and carbon and in addition may contain several other elements based on their type.

Complex organic molecules are made up of many single units linked together usually by covalent bonds. The units may be all of the same type or the polymer may contain several different types of monomers, this depends on the complexity and type of the organic molecules.

All life forms are made up of four types of organic compounds that are carbohydrates, lipids, proteins, and nucleic acids.

The complex organic molecules are known as polymers which means many units.