Which element is present in all organic molecules?

• A. $O$xygen
• B. $S$ulfur
• C. $C$arbon
• D. $N$itrogen

Answer: (C)

Verified step by step guidance

1. Understand the definition of organic molecules: Organic molecules are primarily composed of carbon atoms bonded to hydrogen, oxygen, nitrogen, and other elements.
2. Recognize that the key characteristic of organic chemistry is the study of carbon-containing compounds, which means carbon is the central element in all organic molecules.
3. Note that while elements like oxygen, nitrogen, and sulfur are common in many organic compounds, they are not present in every single organic molecule.
4. Recall that hydrocarbons, which are the simplest organic molecules, contain only carbon and hydrogen, demonstrating that carbon is essential and always present.
5. Conclude that the element present in all organic molecules is carbon, as it forms the backbone of organic chemistry.