Did the earth always have enough oxygen to support aerobic respiration? In your answer describe the important organism(s) involved in the evolution of photosynthesis. Why were these/this organism important to forming today's current environment. Use the following websites to support your answer. You must cite the websites posted below and any other sources that you use to answer the post using APA 7 rules. Articles to read:

https://evolution. berkeley. edu/evolibrary/news/170503_cyanobac teria (Links to an external site.)

https://www. scientificamerican. com/article/timeline-of-photosynthe sis-on-earth/