Explain the ecological roles of prokaryotes: decomposers, producers, nitrogen fixers, pathogens, and various symbioses and recognize that cyanobacteria are the only group that has evolved the ability to carry out oxygen-producing photosynthesis

The ecological role of prokaryotes is : fixing nitrogen to be used by producers, producing organic carbon of the atmospheric oxygen.

Explanation:

1. Decomposers:  Organisms that break down dead organisms as well as waste products  to unlock the supplies of carbon, nitrogen and other elements. Releasing CO₂, breaking downg carbon into minerals to be released back into the environment.

2. Producers: Converting CO₂ into O₂, main food source of life.

3. Nitrogen fixers: Prokaryotes that converts atmospheric N₂ into usable compounds (nitrates, ammonium) for plants to be able to metabolize.

4. Pathogens: Can be diseases that affect certain species and change the environment.

5. Various symbioses: