Multicellular life found its way
Due to the sudden, dramatic rise in oxygen in our planet’s atmosphere, most microbes began cooperating with each other to overcome the drastic environmental change that cyanobacteria had caused. As a result, the first examples of mutually beneficial relationships appeared.

According to scientists, smaller microbes chose to live inside bigger ones functioning as organelles. In the long term, this gave birth to new complex cells, known as eukaryotic cells, which boasted specialized parts playing specialized roles that supported the whole organism.