Help please 400 words no links

(put in): The answer is tiny organisms known as cyanobacteria, or blue-green algae. These microbes conduct photosynthesis: using sunshine, water and carbon dioxide to produce carbohydrates and, yes, oxygen. What it looks like is that oxygen was first produced somewhere around 2.7 billion to 2.8 billon years ago. (this is the best I can do.)

The reaction will shift to the right