Prokaryotic organisms belong to the kingdom Monera, which contains bacteria. The main classes of bacteria are eubacteria and archaebacteria. These prokaryotic organisms are unicellular and can live in different environments.
Cyanobacteria, which are blue-green algae, belong to the eubacteria class. Prokaryotes can be autotrophs or heterotrophs. Autotrophs like blue-green algae can make their own food, while heterotrophs cannot do this. Some bacteria types are also decomposers in nature that consume dead matter and waste. Prokaryotic organisms reproduce through binary fission.
Bacteria can exist in many different types of environment, and can be either harmful or beneficial. For example, some types of bacteria can cause disease, and other are found in the digestive system and do no harm. Similarly, some types of archaebacteria can live in very extreme conditions like in a hot sulfur spring.