Approximately how long after the Solar System formed did it take for oxygen to get to within 80 percent of its present abundance in the Earth's atmosphere?
A) 4 billion years
B) 1 billion years
C) 400 million years
D) 1 million years
E) Oxygen was always a primary component of the Earth's atmosphere.

Question

Quizplus · Accepted Answer

Oxygen reached about 80% of its present abundance in the Earth's atmosphere approximately 4 billion years after the Solar System formed, primarily due to the Great Oxidation Event which occurred around 2.4 billion years ago.

Approximately How Long After the Solar System Formed Did It