Whoo the owl

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Across
  1. 1. What is xenon's periodic number?
  2. 3. the smallest and only even prime number?
  3. 4. How many legs does a spider have?
  4. 6. How many deadly sins are there?
Down
  1. 1. How many seasons are in a year?
  2. 2. How many months in a year?
  3. 5. How many primary colours are there?
  4. 6. How many wheels does a Ural-4320 have?