Across
- 7. black gold
- 8. source of all energy
- 9. oil has not been processed yet
- 11. used to tar roads
- 14. partly decomposed vegetable matter from acidic, boggy ground, dried for use as fuel
- 15. does not run out
- 16. narrow long opening or crack
- 17. the process of burning
- 19. soft brownish coal
- 20. a black rock consisting mainly of carbon from fossils
Down
- 1. the process where plants generate and store energy in leaves and roots
- 2. the gas released by plants during the daytime
- 3. coal ground into small pieces to a powder form
- 4. natural fuel such as coal or gas formed from remains of animals and plants
- 5. squeezed together
- 6. a renewable power source
- 10. process of injecting liquid at high pressure into subterranean rocks.
- 12. a large fan which turns very fast
- 13. consisting largely of methane
- 18. turned by a turbine to produce electricity
- 20. Methane