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Across
  1. 4. Microscopic single-celled organisms?
  2. 8. Flow of electric charge through a conductor?
  3. 10. Essential macromolecule made of amino acids?
  4. 11. Process plants use to make glucose using sunlight?
  5. 13. Measure of electric potential in a circuit?
  6. 15. Force pulling objects toward Earth’s center?
Down
  1. 1. Green pigment vital for photosynthesis?
  2. 2. Instrument for checking temperature?
  3. 3. Force that slows down motion between surfaces?
  4. 5. Cell structure containing DNA?
  5. 6. Element necessary for respiration?
  6. 7. Device used to observe distant objects in space?
  7. 9. Cell that carries signals in the nervous system?
  8. 12. Smallest unit of a chemical element?
  9. 14. Phase change from liquid to gas?