Answer:
A organism is most likely responsible for first producing oxygen in Earth's early atmosphere is explained below in details.
Explanation:
The answer is little organisms identified as cyanobacteria or blue-green algae. These microorganisms carry photosynthesis: practicing sunshine, water, and carbon dioxide to compose carbohydrates and, yes, oxygen. Earth's oxygen but the largest (70%) of the oxygen in the environment is generated by oceanic plants. The ocean creates oxygen through the plants that exist in it.