earth day

4. The complex system of relationships between living things and their environment.
9. Global changes in temperature, wind patterns, rainfall, etc. mainly caused by the burning of fossil fuels like coal and oil.
10. The protection and preservation of natural environments and resources.
11. Rain that contains harmful chemicals that collect in the atmosphere when fossil fuels are burned.
12. A fuel like oil or coal formed from very old plant and animal fossils.
13. To give money or goods to an organization you want to help or support.

1. Releasing no greenhouse gases like carbon-dioxide or methane.
2. A thick dirty cloud at ground level caused by pollutants reacting to sunlight.
3. A gas that's released when carbon is burned (for example coal or oil), or when people or animals breathe out.
5. Can be used without running out, esp. of energy sources like solar and wind.
6. The planting of trees and plants to help a damaged or destroyed forest recover.
7. To share a car instead of driving one alone.
8. To make something new from materials that have been used before.