In the classification of matter, organic compounds are defined by the presence of which element?

• A. Oxygen (O)
• B. Nitrogen (N)
• C. Hydrogen (H)
• D. Carbon (C)

Answer: (D)

Verified step by step guidance

1. Understand that the classification of matter involves categorizing substances based on their composition and properties.
2. Recognize that organic compounds are a major class of compounds studied in chemistry, particularly those related to living organisms.
3. Recall that organic compounds are primarily defined by the presence of the element carbon (C) in their molecular structure.
4. Note that while elements like oxygen (O), nitrogen (N), and hydrogen (H) are often found in organic compounds, they do not define the class itself.
5. Conclude that the key element that characterizes organic compounds is carbon (C), which forms the backbone of these molecules.