Across
- 4. the amount of lead that is considered safe (a number)
- 6. protects us from UV rays in the stratosphere, but is a pollutant in the troposphere
- 8. a geographic area that has a common drainage location for water
- 9. a measure of the suspended particulates in water
- 10. the liquid that accumulates in landfills
- 13. an organism that gets impacted by bleaching
- 14. three of the answers to this crossword are numbers, put them in ___ order to get the code for the next lock
- 15. the most efficient type of irrigation
- 16. the number of layers in the atmosphere BELOW the thermosphere
- 17. practices that will allow the repeated use of resources for generations without running out
- 20. a problem species that is not native
Down
- 1. the non-living components of an ecosystem.
- 2. a type of power generated by moving water, usually in a dam
- 3. the chemical name for natural gas
- 5. a type of organism that gets its energy from the sun directly
- 7. the system in living organisms that regulates hormones and development
- 11. the type of growth demonstrated by a J-shaped curve
- 12. a type of extraction that obtains natural gas by fracturing the rocks
- 18. if the growth rate is 10 percent, then the doubling time is ___ years
- 19. type of soil that has a relatively even mix of sand, silt and clay