Final answer:
The unique chemistry of carbon allows it to form a wide variety of organic compounds through covalent bond formation with itself and other elements.
Step-by-step explanation:
The vast number of organic compounds is due to the unique chemistry of carbon. Carbon has four valence electrons, which allows it to make four separate covalent bonds in compounds. It can bond to itself repeatedly, forming long chains and ringed structures. Carbon also readily forms covalent bonds with other elements, such as hydrogen, oxygen, nitrogen, and halogens, leading to the creation of a wide variety of organic compounds.