Across
- 2. The change in form
- 4. A change that happens because of some kind of action
- 5. A mixture of methane and other gases formed underground and used for energy
- 6. To organize into groups based on a system
- 8. A natural substance made from one or more minerals
- 11. Energy produced by moving water
- 13. A resource that is replenished at a slower rate than it is used
Down
- 1. A material supplied by nature that is used by humans and other organisms
- 3. material made by nature at least as quickly as people use it
- 7. The presence of harmful substances in the environment
- 9. – Able to produce the effect wanted without wasting time or energy
- 10. A naturally occurring, nonliving substance
- 12. The protection and care of rivers, forests, and other natural resources