The kingdom Monera includes organisms that are single-celled known as bacteria. The microorganisms in the kingdom Monera are considered as the most ancient living forms on earth. The kingdom is divided into two groups Archaebacteria and Eubacteria. All the organisms of this kingdom are prokaryotes. These cells do not have a nuclear membrane, the chromosome is single and circular, they also lack membrane-bound cellular organelles. This kingdom includes bacteria, cyanobacteria, mycoplasma, etc. They are unicellular organisms and do not have a specific mode of nutrition. They can be either aerobic or anaerobic. These organisms have a cell wall that is made up of peptidoglycans. The cell organelles are not membrane-bound.