There was so much oxygen 2.2 billion years ago such that it cannot be computed. In the present day, most of the oxygen has been reduced to metal oxides.
0.1
how much oxygen was in the Precambrian time?
From primitive bacteria that produced oxygen as a waste product.
No. Earth itself is "only" about 4.6 billion years old. The first life may have emerged about 4 billion years ago.
Sort of false - it was about 1.5 billion years ago.
Evolution of Eukaryotes took approximately 1.5 billion years .
2 billion years ago ... You Plato user huh....
About the same. About a half billion years ago it was significantly higher, and more than a billion years ago it was lower, much lower. Before 1.5 or 2 billion years ago there was no free oxygen in the atmosphere, before 3 billion years ago there wasn't any.
oxygen
The Carboniferous period, during which oxygen amounted to 35% of the atmosphere by volume (this was around 300 million years ago). Nowadays the amount is 20.95%.
2.4 billion year ago :D
Oxygen is the element that transformed Carbon Dioxide atmosphere a billion years ago to what you breathe.
After plants developed chlorophyll and multiplied to the point where they could "pollute" the primal atmosphere, somewhere between 1 and 2 billion years ago.
From primitive bacteria that produced oxygen as a waste product.
the earth
accumulate
Oxygen, for one thing.
Algae activity
More than 2 billion years ago, trees and plants began producing oxygen. They do this by feeding off carbon dioxide released by living beings.