Cyanobacteria are classified under :

Archaebacteria and eubacteria are two main groups that are included in the Kingdom Monera. Eubacteria can be further classified into bacteria and cyanobacteria.

These bacteria differ in several aspects, including their genetic composition and environmental adaptations.

• Archaebacteria are often found in extreme environments, such as hot springs, salty lakes, or acidic conditions, where other life forms might not survive. They are known for their ability to thrive in such harsh conditions, with some capable of producing energy from chemicals in the absence of light. Archaebacteria have a unique cell wall structure and distinct biochemistry compared to eubacteria, making them a separate group.
• Eubacteria, on the other hand, are more common and can be found in a wide variety of environments, from soil to water to the human body. They are classified into two subgroups:
  1. Bacteria: These are the more conventional types of bacteria that include pathogens as well as beneficial bacteria involved in processes like nitrogen fixation.
  2. Cyanobacteria (also known as blue-green algae): These organisms are capable of photosynthesis, producing oxygen as a byproduct. Cyanobacteria are essential for many ecological processes, particularly in the formation of oxygen-rich atmospheres.

The division between archaebacteria and eubacteria highlights their significant evolutionary differences, and together, they form the diverse range of organisms that make up the kingdom Monera.