Science 7b ~Alex

12345678910111213141516171819
Across
  1. 2. water under ground
  2. 4. environmental protection agency
  3. 5. things draining into water, polluting it
  4. 7. smoke and fog
  5. 9. number of billions of people in the world
  6. 10. a greenhouse gas that is recognisable by smell
  7. 11. compound of oxygen with another element
  8. 13. able to be maintained at a certain level
  9. 15. the number of people plants or animals that can be sustained
  10. 18. man made substance that causes some plants to spot
  11. 19. natural fuel such as coal
Down
  1. 1. the total mass of organisms in a given area or volume
  2. 2. gas that contributes radiation
  3. 3. limit of population growth due to resources
  4. 6. farming ground must be this
  5. 8. percent of pollution caused by transportation
  6. 12. pollutant in the air that joins with smog and reduces visibility
  7. 14. farming
  8. 16. the state of being able to see or be seen
  9. 17. volatile organic compounds