Combustion cross word

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Across
  1. 1. a poisonous gas which we can not see
  2. 5. what things are required to make something
  3. 6. everywhere around the earth and has many gases
  4. 7. an item required for combustion
  5. 9. something water is mostly made of
Down
  1. 1. the process of fire burning
  2. 2. something the atmosphere is mostly made from
  3. 3. if something can catch on fire or not
  4. 4. an element that requires oxygen to work
  5. 5. an item that powers lots of items
  6. 8. a waste substance created from the use of fuel