Lesson from history for a better future

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Across
  1. 2. Fighting between countries.
  2. 3. The Earth and everyone on it.
  3. 5. The time that comes after now.
  4. 7. When he have no fight.
  5. 9. To gain new knowledge.
Down
  1. 1. To make something different.
  2. 4. The state of being alive.
  3. 6. What we measure in seconds, minutes, and hours.
  4. 7. Human together.
  5. 8. The time before now.