ENERGY

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Across
  1. 2. Energy that always changes from high to low quality forms
  2. 6. The energy stored in an object
  3. 7. Available in limited supply
  4. 8. A layer of material laid down naturally
  5. 9. A process in which resources can be renewed
  6. 10. The energy of motion
  7. 13. Convert crude oil into usable forms of oil
Down
  1. 1. A principle
  2. 3. Energy is neither created nor destroyed
  3. 4. A machine that generates electricity
  4. 5. A solid fossil fuel made up of almost pure carbon
  5. 7. Underground deposits of gas, mostly methane
  6. 11. To pollute
  7. 12. A thick liquid fossil fuel formed underground