<h2>Cyanobacteria </h2>
Explanation:
Simple cyanobacteria (single-celled organisms that can produce oxygen through photosynthesis) played a key role in providing Earth’s atmosphere and oceans with oxygen
Cyanobacteria or the blue green algae are the only bacteria that contain chlorophyll A, a chemical required for oxygenic photosynthesis, the process which uses carbon dioxide, water and sunlight to produce oxygen and glucose (sugars) for energy
In this process chlorophyll A helps in capturing the energy from sunlight
In addition to chlorophyll A, blue-green algae also contain the pigments phycoerythrin and phycocyanin, which give the bacteria their bluish tint
All the above characteristics of cyanobacteria can be used as a source of renewable energy by converting sunlight into electricity