An exothermic reaction:

**The reasoning** Think of "exo-" like "exit" — heat **exits** the system. In an exothermic reaction, chemical bonds break and form, and when the new bonds release more energy than was needed to break the old ones, that extra energy escapes as heat into the surroundings. Classic examples: burning wood, rusting iron, or mixing acid and water (the container gets hot, right?). The reaction vessel feels warm because heat is being **released** to your hand. **Why the wrong options tempt you** **A (Absorbs heat)** — This describes *endothermic* reactions (think "endo-" = "into"). Easy to mix up if you don't anchor the prefixes. **C (No temperature change)** — Sounds scientific, but reactions that don't release or absorb noticeable heat are rare and wouldn't be called "exothermic." **D (Requires light)** — This confuses reaction conditions with energy flow. Some reactions need light to *start* (like photosynthesis), but that doesn't define whether they release or absorb heat. **Quick takeaway** **Exo = Exit:** exothermic reactions release heat and warm their surroundings, just like how exhaling pushes air *out* of your body.