thing

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Across
  1. 4. : Essential gas for human respiration
  2. 5. : Branch of science dealing with matter and energy
  3. 7. : Tool engineers use to measure length precisely
Down
  1. 1. : Study of living organisms
  2. 2. : Opposite of “synthetic”; naturally made
  3. 3. : Source of renewable energy from moving air
  4. 5. : Waste material that can harm nature
  5. 6. : Device that converts sunlight into electricity
  6. 8. : Machines that can perform tasks automatically