WWI crossword Puzzle

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Across
  1. 2. it was 6-7 feet deep, featuring firing steps dugouts for protection, and zigzag patterns to prevent enemy soldiers from shooting down the entire line.
  2. 7. countries believe military power determines everything
  3. 8. Countries invade another country's land and resources
  4. 10. People think their ethnics are better then others'
  5. 11. the heir of A-H, and he was assassinated by a Serbian
  6. 12. The country where the Treaty of Versailles was signed
Down
  1. 1. Two words including: Germany, Austria-Hungary, Ottoman Empire
  2. 3. The country quitted the WWI because of their own revolution
  3. 4. The new weapon mainly used underwater.
  4. 5. two words including: Britain, France, and Russia at the beginning of the WWI
  5. 6. The country joined the WWI when Russia quitted
  6. 9. countries make treaties with each other for protection