Across
- 4. A layer of soil containing mostly decaying animal and plant matter
- 6. A substance applied to plants to add to nutrients in the soil
- 7. When a large area of land becomes developed
- 8. A layer of soil containing decaying organisms and rock fragments
- 9. When desert-like conditions spread into new areas
- 11. A period where there is less rainfall in an area than usual
- 12. Depletion When, from a lack of nutrients, soil becomes less fertile
- 16. The movement of soil or rock through water, wind, or ice
- 17. Layer A layer of a form of oxygen that protects the Earth from the sun's UV rays
- 18. The top layer of soil containing plant matter
- 19. A natural, radioactive gas that is a common source of indoor air pollution
Down
- 1. Man-made gasses composed of fluorine and chlorine
- 2. The rock that makes up Earth's crust
- 3. Pollutants released into the air
- 5. Smog The result of ozone and sunlight reacting near the Earth's surface
- 9. When a large area of trees are removed by humans
- 10. Inversion A process in which warm air traps polluted air close to the Earth's surface
- 13. Resource Something useful to humans that occurs naturally in the environment
- 14. Rain Precipitation that is much more acidic than usual
- 15. Reclamation To restore an area of land to a more productive state