Question

"An oxygen-rich environment would cause a mass extinction of prokaryotes."

Answer 1

Answer:

"An oxygen-rich environment would cause a mass extinction of prokaryotes."  Supports current scientific theories of how life might have originated on Earth.

Explanation:

The reacting power of oxygen increases rigorously in an oxygen- rich environment, which leads to huge fire ignition even with the slightest spark which is generally non hazardous at all. Many prokaryotic organisms do not need oxygen as they perform anaerobic respiration. Oxygen is dangerous for some prokaryotes.  

There were some prokaryotic organisms who were giving out oxygen as waste. Such excess amount of oxygen was hazardous for the environment and hence mass extinction was required to keep a check on the excess amount of oxygen being released.