Across
- 4. alternative energy that uses falling water
- 6. energy from the sun
- 8. coal is considered a ________ resource
- 10. fossil fuels are a more popular source of energy because they're _____.
- 13. renewable resources do not cause ___________
- 14. solar energy is ________
Down
- 1. an increase in green house gasses affects the earth's _______
- 2. materials in the environment that are useful to people
- 3. energy from living or once-living things
- 5. a resource that cannot be easily replaced is a __________ resource
- 7. another word for petroleum
- 9. how we obtain our fossil fuels
- 11. coal, natural gas, and petroleum
- 12. energy produced by the heat within Earth