Final answer:
The factor involved in forming the paused state of RNA pol II is the o-factor, which allows for specific gene transcription in prokaryotes.
Step-by-step explanation:
The factor involved in forming the paused state of RNA pol II is the o-factor. In prokaryotes, RNA polymerase can transcribe RNA at a high rate, and from random sequences in the chromosome when the o-factor is absent. However, when the o-factor is bound to the RNA polymerase, the complex recognizes and binds to the promoter sequence of a gene, resulting in slower transcription but only of specific genes. The o-factor lineage can be traced back beyond archaea to the eubacteria.