Answer:
oxygenation of the atmosphere
Explanation:
The "Great Oxidation Event" was one of the most important things happening on this planet. Without it, there could never be animals breathing oxygen, like insects, fish, and certainly humans. Moreover, this moment of our planet was one of the main responsible for the evolution of eukaryotes.
For decades, scientists have worked to understand how and why oxygen emerged. And they suspect that life itself was responsible for creating the air we breathe.
The latest findings suggest that life was undergoing a tremendous transformation before the "Great Oxidation." An evolutionary leap that helps explain what we know today.
Formed 4.5 billion years ago, the Earth, at the time of the Great Oxidation, was already inhabited. But only by unicellular organisms. It is not exactly clear when life began on the planet, but the oldest fossils of these microorganisms date back at least 3.5 billion years ago. This suggests that life had existed on earth almost 1 billion years before the "Great Oxidation." From the moment oxygen spread through the atmosphere, it was possible for these organisms to evolve into more complex life forms.
