Across
- 4. type of precipitation that forms when waste gases from automobiles and power plants combine with moisture in the air
- 6. layer that prevents most harmful ultraviolet (UV) radiation from reaching Earth
- 7. to appear or happen
- 11. type of natural resource that can be replenished by natural processes at least as quickly as it is used
- 12. type of natural resource that will not run out, no matter how much of it people use
- 13. scientific observation that Earth’s average temperature is increasing
- 15. something that has two different components performing essentially the same task
Down
- 1. act of meeting human needs in ways that ensure future generations also will be able to meet their needs
- 2. part of the environment that supplies a material that is useful or necessary for the survival of living things
- 3. type of smog/air pollution that is formed when sunlight reacts with waste gases from the burning of fossil fuels
- 5. type of natural resource that is being used up faster than it can be replaced by natural processes
- 8. contamination of the environment with substances that are harmful to life
- 9. manufacturing new products out of used products
- 10. type of energy creating heat from within Earth
- 14. mixture of gases that forms a layer around Earth