Respiration releases energy from:

**The reasoning** Respiration is your body's way of unlocking stored energy, like withdrawing money from a bank account. That "account" is **glucose** (a sugar from the food you eat). The process follows this equation: **Glucose + Oxygen → Carbon dioxide + Water + ENERGY (ATP)** Think of glucose as fuel and oxygen as what helps burn it. The energy released powers everything — walking, thinking, even reading this. The principle here is **cellular respiration** — your cells break down glucose molecules to release the chemical energy trapped in their bonds. **Why the wrong options tempt you** - **Oxygen (C)**: You breathe it in, so it *seems* like the energy source. But oxygen is just the helper that breaks down glucose — like a matchstick that lights the firewood, not the firewood itself. - **Water (A)**: Water is a *product* of respiration, not the source. It's what's left after energy is released. - **Protein (D)**: Proteins *can* provide energy in emergencies, but glucose is the primary, everyday fuel your body prefers. **Quick takeaway** *Glucose is the fuel; oxygen is just the spark that releases its stored energy.*