Answer:
banded iron formations
Explanation:
The creation of the necessary characteristics for life to happen on earth, we needed to have an atmosphere with oxygen available for life as we know it with carbon based organisms, in the begining of the planet earth, a little bacteria that was present on a archaic "soup" that we could call an ocean, called cyanobacteria started to do processes that realesed oxygen into the atmosphere and created iron formations in the ocean.
