Why was the appearance of oxygen in the atmosphere a crucial event in the history of life?

+1 vote

 

  

Aerobic respiration was now a possibility.

  

Free oxygen was able to react more freely with iron to form iron oxides.

  

Cyanobacteria no longer thrived.

  

Oxygen allowed the appearance of microscopic algae in the fossil record 2.1 billion years ago.

 

asked Dec 28, 2012 in Biology by anonymous
    

1 Answer

0 votes

 

Aerobic respiration was now a possibility.

 

answered Dec 28, 2012 by anonymous



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