I am an American biologist that contributed to the theory of biological kingdoms. I am responsible for the fouth kingdom, Monera
I'm gonna tell you some characteristics:
They are typically unicellular organisms (but one group is mycelial). The genetic material in these organisms is the naked circular DNA. A nuclear envelope is absent. Both, ribosomes and simple chromatophores, are the only subcellular organelles in the cytoplasm.
Sap vacuoles do not occur. Instead, gas vacuole may be present. The predominant mode of nutrition is absorptive but some groups are photosynthetic (holophytic) and chemosynthetic.The organisms are non-motile or move by the beating of simple flagella or by gliding.
This the four-kingdom classification that I proposed: