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Across
  1. 3. force that keeps planets in orbit
  2. 4. flying mammals
  3. 6. energy in motion
  4. 7. appears before thunder is heard
  5. 8. moon and sun gravitational pull
Down
  1. 1. saline solution
  2. 2. resistance to motion
  3. 5. list of steps
  4. 7. light emitting diodes