Which of the following is likely the greatest impact that organisms have ever had on Earth?
A)Early cyanobacteria released hydrogen to Earth's atmosphere during the water-splitting step of photosynthesis.
B)Early cyanobacteria released carbon dioxide to Earth's atmosphere during the water-splitting step of photosynthesis.
C)Early cyanobacteria released oxygen to Earth's atmosphere during the water-splitting step of photosynthesis.
D)Early cyanobacteria released nitrogen to Earth's atmosphere during the water-splitting step of photosynthesis.

Question

Quizplus · Accepted Answer

The release of oxygen into Earth's atmosphere by early cyanobacteria during photosynthesis had the greatest impact on Earth. This event, known as the Great Oxygenation Event, began about 2.4 billion years ago and was instrumental in the evolution of complex life on Earth. Oxygen allowed for the development of aerobic respiration, which is much more efficient at producing energy than anaerobic respiration. This allowed organisms to become larger and more complex, ultimately leading to the development of multicellular life. Additionally, oxygen in the atmosphere allowed for the formation of the ozone layer, which protects life on Earth from harmful UV radiation from the sun.

Which of the Following Is Likely the Greatest Impact That