List at least three examples of how microbial phototrophs are important clinically and environmentally

Microbial phototrophs are organisms like algae and cyanobacteria which carry out their cellular metabolic processes by using the energy from light.

These are important environmentally as they are present on the surfaces exposed to light in terrestrial as well as aquatic environments. Here, algae and cyanobacteria are the major primary producers of energy as they generate energy and reduce carbon dioxide. This helps to provide the environment with organic substances and oxygen.

Clinically the cyanobacteria has contributed to many aspects of human life like it is used for several medical purposes. Many Proterozoic oil deposits are attributed to the activity of cyanobacteria.

well, i believe that the answer is 2. : 3