The two correct statements that describe cyanobacteria are:
- Cyanobacteria lived in the ocean
- Cyanobacteria were the first photosynthesizing organisms
Cyanobacteria are known to be some of the earliest life forms on Earth and were significant in the development of oxygen in the atmosphere through photosynthesis. They are prokaryotic organisms, meaning they do not contain a nucleus, and they played a crucial role in increasing oxygen levels rather than decreasing them.