The U.S.A., the country of contrasts

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Across
  1. 3. the opposite of flat land
  2. 5. This area is densely ...
  3. 6. not saving ressources/material/water, energy, etc.
  4. 8. ... USA/US is a country of contrasts
  5. 12. city/ towns
  6. 13. unit to measure the temperature/ degrees ...
Down
  1. 1. opposite of densely
  2. 2. opposite of city/towns
  3. 4. many people are in a small space
  4. 7. what you see around you when you are somewhere with a view
  5. 9. rich
  6. 10. huge/very, very big
  7. 11. over how many hundred million citizen is the US' population?