Which of the Following Statements About Oxygen and Ancient Earth

question 104

Multiple Choice

Which of the following statements about oxygen and ancient Earth is true?

• A) The atmosphere of early Earth contained almost as much free oxygen as present-day Earth, but most of this oxygen was lost in the Cambrian.
• B) Early bacteria generated free oxygen as a by-product of the chemical splitting of water.
• C) The oxygen-generating cyanobacteria have gone extinct.
• D) All of the above
• E) None of the above

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