Here's why:

* Organic Chemistry: The branch of chemistry that studies compounds containing carbon is called organic chemistry. This is because carbon's unique ability to form long chains and complex structures with other elements, including hydrogen, oxygen, and nitrogen, is the foundation for the vast diversity of molecules found in living things.

* Biomolecules: The four major classes of biomolecules (carbohydrates, lipids, proteins, and nucleic acids) are all based on carbon skeletons.

* Building Blocks of Life: Carbon forms the backbone of the molecules that make up our bodies and all living organisms, including DNA, proteins, and carbohydrates.

While other elements are also present in organic matter, carbon serves as the fundamental building block that makes organic molecules possible.