Oxygen Cycle and ozone layer

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Across
  1. 5. _________ of metals leads to formation of rust
  2. 6. CFC gas used in refrigerators
  3. 9. The full form of o2 is
  4. 11. oxygen cycle is a type of _______ cycle
  5. 12. the process in which oxygen is replenished in the environment
Down
  1. 1. ozone gas is ______ in nature
  2. 2. organic molecules use oxygen in the process of
  3. 3. One atom of _______ can destroy over 100000 ozone molecules
  4. 4. ______ pact signed in 1987 to help save ozone layer
  5. 7. Natural source of ozone layer depletion
  6. 8. the scientist credited with discovering the ozone hole
  7. 10. most of the oxygen on Earth is contained inside