Origin of Oxygen

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Across
  1. 3. Created from a branch of the Milkyway, spinning disk of dust and debris creates our solar system, 5 billion years before present (3)
  2. 6. Carl Sagan is an example of this animal made of 65% oxygen (12)
  3. 9. created 2.7 billion years ago, this photosynthetic bacteria started to create O2 (9)
  4. 11. When the sun expands to this size, our planet will be engulfed and oxygen gas will be dispersed in space (15)
  5. 13. heavier element formed in the creation and death of stars, when stars die they disperse this element into space and condense into new stars and planets (4)
  6. 14. Carl Sagan's favorite tasty treat, contains oxygen (13)
Down
  1. 1. Abundant evolution = complex creatures and eventually humans (11)
  2. 2. early earth had oceans and volcanism made of/produced by this compound featuring oxygen (6)
  3. 4. Created 4.5 billion years ago, started as a fiery molten planet, now home to 8 billion people (5)
  4. 5. composed most of earths early atmosphere (7)
  5. 7. 300 million years after the big bang, created from condensing primordial gas (2)
  6. 8. The process of recycling oxygen through lithosphere, biosphere and atmosphere (14)
  7. 9. water vapor split, H went into space and O was pulled out of the atmosphere and into minerals on the earths...(8)
  8. 10. the origin of the universe, creation of H and He (1)
  9. 12. created from the abundant atmospheric gas, layer that shielded the Earth from solar radiation O3, (10)