Which event was most directly responsible for increasing oxygen in Earth's atmosphere?
A) The cooling of the planet
B) The emergence of eukaryotes
C) The development of multicellularity
D) The evolution of photosynthesis
E) The rise of prokaryotes

Question

Quizplus · Accepted Answer

The evolution of photosynthesis, specifically oxygenic photosynthesis, by certain prokaryotes (such as cyanobacteria) was responsible for the significant increase in oxygen levels in the atmosphere. This process began approximately 2.4 billion years ago and gradually led to the Great Oxygenation Event (GOE) around 2.3 billion years ago, where oxygen levels rose from less than 1% to around 10%. This paved the way for the emergence and diversification of aerobic organisms.

Which Event Was Most Directly Responsible for Increasing Oxygen in Earth's