Author Question: How did oxygen (O2 ) get into Earth's atmosphere? A) It was captured from the solar nebula. B) ... (Read 73 times)

rachel9

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How did oxygen (O2 ) get into Earth's atmosphere?
 
  A) It was captured from the solar nebula.
  B) It was outgassed from volcanoes.
  C) It came from chemical reactions with surface rocks.
  D) It was released by life through the process of photosynthesis.

Question 2

An intermediately wound barred spiral galaxy would be
 
  A) BS2.
  B) BSE.5.
  C) SBb.
  D) S2B.
  E) SIrr.



amanda_14

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Answer to Question 1

D

Answer to Question 2

C



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