What made the increase in atmospheric oxygen that began at approximately 2.5 billion years ago?
a) Volcanic eruptions
b) Photosynthetic bacteria
c) Cyanobacteria
d) Meteorite impacts

Respuesta :

Answer: c) Cyanobacteria.

Explanation:

Cyanobacteria, also known as blue-green algae, were one of the first organisms to perform photosynthesis on Earth.

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