"I'm Finished" Crossword EXTRA HARD

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Across
  1. 1. – substance that speeds up a chemical reaction
  2. 3. – medieval system of lords, vassals, and serfs
  3. 5. – product of all positive integers up to n
  4. 9. – a narrow inlet between steep cliffs formed by glaciers
  5. 11. – the powerhouse of the cell
  6. 12. – rate of change in calculus
Down
  1. 2. – solid changing directly to gas
  2. 4. – intellectual movement emphasizing reason and science
  3. 6. – a chain of islands
  4. 7. – a narrow strip of land between two seas
  5. 8. – religious wars between Christians and Muslims
  6. 10. – positively charged particle in an atom