The taxon called a kingdom is the largest group used in helping us to see the relationship among micro-organisms. A system, that has not been universally accepted has been proposed by Carl Woese and George Fox. These scientists assign all living organisms to three super kingdoms called Archaebacteria, Eubacteria, and Urkaryotae. Because bacteria are found everywhere and so numerous, the bacteria are placed in Eubacteria; and all other more complex organisms having a distinct cell nucleus are placed in Urkaryotae.