Gr.8-Coal and Petroleum

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Across
  1. 3. Natural gas mainly contains ______.
  2. 6. _____is responsible for global warming.
  3. 8. ________ is a mixture of hydrogen, methane, carbon monoxide and other gases.
  4. 9. _________ is used for surfacing of roads.
Down
  1. 1. _______ contains 90% of carbon.
  2. 2. _______ is used to prepare coke and coal tar.
  3. 4. Composition of petroleum.
  4. 5. _______ is known as brown coal.
  5. 7. Components obtained by refining of petroleum.