Common bacteria belong to the kingdom Monera. This kingdom includes all prokaryotic organisms, which are unicellular and lack a defined nucleus and membrane-bound organelles. Within Monera, bacteria are generally classified as Eubacteria, the common bacteria, while Archaea (formerly Archaebacteria) represent another distinct group of prokaryotes

. More recent classification systems sometimes separate bacteria into the domain Bacteria, distinct from Archaea, and may subdivide further into multiple kingdoms within those domains. However, the traditional and widely accepted kingdom for common bacteria remains Monera

. In summary:

• Kingdom: Monera
• Characteristics: Prokaryotic, unicellular, no nucleus
• Includes: Common bacteria (Eubacteria) and archaea (Archaebacteria) as subgroups

This classification is still commonly used in biology education and many taxonomic references