BIOFUEL

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Across
  1. 2. worldwide system of computer networks
  2. 4. material such as coal, gas, or oil that is burned to produce heat or power.
  3. 6. the study of living organisms
Down
  1. 1. liquid that is made up of organic molecules
  2. 3. the strength and vitality required for sustained physical or mental activity.
  3. 5. all of space and time and their contents
  4. 7. substance that flows freely but is of constant volume, having a consistency like that of water or oil.