Jacob y as in cryptic

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Across
  1. 3. A breathable air that is able to keep us alive
  2. 6. A sign to warn or attract people to something
  3. 7. I was doing some myth testing and I found out it's called _______
  4. 8. A cheimcal reaction when two chemicals combine
  5. 9. It was ______ to get rain here in New South Whales
  6. 10. I was lisening to some _______ sounds
  7. 12. I was reading a news paper with some words that were the same
Down
  1. 1. I saw two words that were _______ that mean the same sound but not same spelling
  2. 2. A game or show you do at a gym for fun or commpetion
  3. 4. A massive brick triangular with mostly a square base
  4. 5. A big hot contry that has some acient builds such as some pyramids
  5. 8. A type of shape that has two circlular sides
  6. 11. I was trying to _______ away a clue to a quest