Underscores for spaces

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Across
  1. 4. Loves_Water
  2. 6. Yes/Nucleus
  3. 9. Lower_to_Higher_Consentrations
Down
  1. 1. Semi_permeable
  2. 2. Hates_Water
  3. 3. Greater_In_Than_Out
  4. 4. Greater_Out_Than_In
  5. 5. No/Nucleus
  6. 7. Covid-19
  7. 8. Acts_like_oil_on_water