Compounds of carbon (life):

**The reasoning** By definition, **organic chemistry** is the study of carbon-containing compounds, especially those found in living organisms. The key connection is: **Carbon + Life = Organic**. Your body, food, DNA, proteins, fats, carbohydrates—all contain carbon chains and are called organic compounds. This term comes from "organism" because scientists originally found these compounds only in living things. Today we know we can make them in labs too, but they're still called organic because of their carbon-based structure and relationship to life. **Why the wrong options tempt you** **(A) Inorganic** — You might think "life" sounds scientific and clinical, so "inorganic" feels right. But inorganic compounds are things like salts, metals, and minerals (NaCl, H₂O, CO₂)—mostly *without* carbon-hydrogen bonds. **(C) Synthetic only** — Yes, we can make organic compounds artificially, but they also occur naturally in all living things. **(D) Radioactive** — Carbon has radioactive isotopes (like C-14), but most carbon compounds in life are stable and non-radioactive. **Quick takeaway** **Organic = Carbon + Life.** Whenever you see carbon compounds related to living things, think "organic chemistry."