CROSSWORD

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Across
  1. 2. Lacking brightness
  2. 3. electromagnetic radiation
  3. 4. reflecting light in large amounts
  4. 5. produced by nature
  5. 8. what light needs to exist
  6. 9. shows your reflection
Down
  1. 1. made by humans
  2. 6. skin disease
  3. 7. the natural science that studies matter
  4. 10. physics that studies properties of light