* Carbon (C): The backbone of all organic molecules. It has the ability to form four bonds, allowing it to create a vast array of complex structures.

* Hydrogen (H): Often found bonded to carbon, it plays a role in defining the shape and properties of organic molecules.

* Oxygen (O): Crucial for functional groups like alcohols, ketones, and carboxylic acids, which impart specific chemical properties.

* Nitrogen (N): Present in amino acids, proteins, and nucleic acids, it's involved in important biological functions.

These four elements make up the vast majority of organic compounds. However, other elements like phosphorus (P) and sulfur (S) can also be found in specific organic molecules, contributing to their unique structures and functionalities.