Across
- 5. finite energy source
- 9. byproduct of burning fossil fuel
- 10. takes millions of years to form
- 12. biofuel is made from
- 13. a biofuel crop used in Brazil
- 14. another term for crude oil
Down
- 1. gas used in cooking and heating
- 2. liquid form of biofuel
- 3. an effect after continuously using fossil fuel
- 4. biofuel produced from vegetable oil
- 6. derived from plant materials
- 7. a non-renewable energy source
- 8. a greenhouse gas emitted by fossil fuel
- 11. fossil fuel used in cars