Biogas

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Across
  1. 2. Not suitable for places without enough ______ animals
  2. 5. A gas produced from cow dung and organic waste.
  3. 6. Biogas is a type of this energy that does not get finished.
Down
  1. 1. Biogas causes ____ effect.
  2. 3. Biogas is safe for this and reduces pollution.
  3. 4. Biogas plants need large amounts of animal ______.