Here's why:

* Organic chemistry is the branch of chemistry that studies the structure, properties, and reactions of compounds containing carbon.

* Carbon's ability to form strong bonds with itself is the foundation of organic chemistry. This allows for the formation of long chains, branched structures, and rings, leading to a vast array of organic compounds.

While some inorganic compounds (like carbonates) contain carbon, the presence of a carbon-carbon bond is generally considered a defining characteristic of organic molecules.