All organic compounds contain which element?

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

Answer: (B)

Verified step by step guidance

1. Understand the definition of organic compounds: Organic compounds are primarily characterized by the presence of carbon atoms bonded to hydrogen atoms, often along with other elements.
2. Recognize that while many organic compounds contain elements like oxygen (O), nitrogen (N), and sulfur (S), these are not universally present in all organic molecules.
3. Identify carbon (C) as the essential element that must be present in all organic compounds, as it forms the backbone of organic chemistry.
4. Recall that the unique ability of carbon to form four covalent bonds allows for the vast diversity of organic molecules.
5. Conclude that the element common to all organic compounds is carbon (C), distinguishing them from inorganic compounds.