Fossil fuels

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Across
  1. 4. a viscous liquid derived from petroleum, especially for use as a fuel or lubricant.
  2. 6. unrefined petroleum.
  3. 7. a sedimentary deposit composed predominantly of carbon that is readily combustible.
  4. 8. a method used to extract natural gas and oil from deep rock formations known as shale.
  5. 10. layer Rocks that contain empty spaces that can be filled with air or water
Down
  1. 1. layer A portion of an aquifer that contains rock material that does not allow water to penetrate
  2. 2. made of coils of wire with electricity passing through them.
  3. 3. domestically produced gaseous fuel
  4. 5. the lowest grade coal with the least concentration of carbon.
  5. 9. Removing unwanted elements from oil