Why does the earth have oxygen and all the other planets do not?

Question: Why does the earth have oxygen and all the other planets do not?
- Keywords:
  oxygen
Asked by Lucy2004simmons to Peter on 18 Nov 2016.
- Peter Boorman answered on 18 Nov 2016:
  
  Hi Lucy,
  
  THAT is a great question! The main reason (I believe) is because the Earth is the only known planet with *plants*, which (through photosynthesis) convert carbon dioxide into oxygen.
  
  Peter

Question: Why does the earth have oxygen and all the other planets do not?