Across
- 2. Natural ___. Found in fossil fuels.
- 4. Humans eat this to obtain energy.
- 6. Salt is a ________.
- 7. There are many types of ______.
- 8. Electricity supply.
- 9. This keeps us warm.
Down
- 1. Used as a source of power.
- 3. We burn ____ to produce heat.
- 5. The ___ produces food for plants.
- 6. A flow of electricity.