Multiple Choice
Which statement 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) Oxygen concentration increased from near zero to near present-day levels in a nearly straight line upwards.
E) Early bacteria generated free oxygen as a by-product of the chemical splitting of carbohydrates.
Correct Answer:
Verified
Correct Answer:
Verified
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