1. Pollution and Human Impact

2. Air that contains harmful chemicals, gases dust, or fumes.

3. Air that contains harmful chemicals, gases dust, or fumes.
Air Pollution

4. A chemical used to control, repel, or kill pests.

5. A chemical used to control, repel, or kill pests.
Pesticides

6. A mixture of decaying vegetation and manure.

7. A mixture of decaying vegetation and manure.
Composting

8. The re-use of materials that would otherwise be considered waste.

9. The re-use of materials that would otherwise be considered waste.
Recycle

10. Supervision and management of rivers, forests, and other natural resources in order to preserve and protect them.

11. Supervision and management of rivers, forests, and other natural resources in order to preserve and protect them.
Conservation

12. To be restored to its original condition

13. To be restored to its original condition
Renew

14. A substance that can be used for the production of energy.

15. A substance that can be used for the production of energy.
Fuel

16. To use again after processing.

17. To use again after processing.
Reuse

18. Resources supplied by nature.

19. Resources supplied by nature.
Natural Resources

20. Unwanted or undesired material left over from the completion of a process (after being used)

21. Unwanted or undesired material left over from the completion of a process (after being used)
Waste