1. Carbon (C): This is the backbone of all organic molecules. Carbon has the unique ability to form four bonds with other atoms, allowing for the creation of complex and diverse structures.

2. Hydrogen (H): Hydrogen is often found attached to carbon atoms in organic molecules. It plays a crucial role in forming covalent bonds and influencing the molecule's shape and properties.

3. Oxygen (O): Oxygen is frequently present in organic molecules, often forming functional groups like hydroxyl (-OH) and carbonyl (C=O). Oxygen contributes to the polarity and reactivity of organic compounds.