Across
- 2. Replaced by natural processes
- 4. Actions taken to protect the environment, such as reducing energy use
- 5. Energy from moving water
- 7. Using natural resources in a way that ensures they will be available for future generations
- 10. Gasses in Earth's atmosphere that trap heat
- 11. Energy from the heat inside of the Earth
- 12. Energy from once-living things, such as plants and animal waste
Down
- 1. The large scale introduction of using machines
- 3. Formed from the remains of dead plants or animals over millions of years
- 6. Actions taken to reduce harmful effects
- 8. Not able to be replaced by nature
- 9. Energy released from the nucleus of an atom