Problem 6

Background and context

Autotropic organisms that are able to convert solar energy into chemical energy are known as phototrophs. Cyanobacteria are evolved from these phototrophs are called blue-green algae. Phototrophic organisms are those which use sunlight as the primary source of energy and carried out photosynthesis. Aerobic organisms are those which cannot live without oxygen whereas anaerobic organisms are which are able to live without oxygen. Anaerobic organisms are able to survive at that time when the atmosphere of Earth has no molecular oxygen.