Across
- 3. The type of reaction where energy is absorbed
- 4. The process by which plants convert sunlight into energy
- 5. A substance made of two or more elements chemically bonded together
- 6. The gas essential for combustion
- 7. An element or compound at the start of a chemical reaction
- 10. The place where photosynthesis occurs in plant cells
- 11. The building blocks of all substances
- 12. The basic unit of life
- 13. The variety of different species in an ecosystem
Down
- 1. A type of fuel formed from the remains of ancient plants and animals
- 2. A reaction that releases energy, often producing heat and light
- 5. A change that results in the formation of new substances
- 8. The theory that explains how species change over time
- 9. A group of cells that work together to perform a specific function