A second rapid increase of oxygen in the atmosphere (the Second Great Oxidation Event) started about __________ years ago.
A) 3 billion
B) 600 million
C) 60 million
D) 6 million

Question

Quizplus · Accepted Answer

The second rapid increase of oxygen in the atmosphere, also known as the Great Oxidation Event, began around 2.4 billion years ago, which is approximately 600 million years after the first increase of oxygen production.

A Second Rapid Increase of Oxygen in the Atmosphere (The