Q: Given a text passage, come up with an appropriate title for it. The title should accurately represent what the main focus of the passage is. The title of a passage may be present in the first few sentences of the passage and/or be referred to multiple times in the passage. The title should be 1-5 words long.
Cyanobacteria / sanobktri / , also known as Cyanophyta , is a phylum of bacteria that obtain their energy through photosynthesis , and are the only photosynthetic prokaryotes able to produce oxygen . The name '' cyanobacteria '' comes from the color of the bacteria ( Greek : ( kyanos ) = blue ) . Cyanobacteria ( which are prokaryotes ) used to be called '' blue - green algae '' . They have been renamed ' cyanobacteria ' in order to avoid the term '' algae '' , which in modern usage is restricted to eukaryotes .
A:
Cyanobacteria