Those that do not show artificial selection are examples A and B.
Answer:
Sigma factors bind to the promoter region of a particular gene and facilitating the binding of RNA Polymerase to the promoter region (formation of the RNA polymerase holoenzyme complex) in order initiate transcription of the gene.
Put simply - Helps RNA Polymerase do it's job.
It could be frictional force or tension force
Idk sorry i need 2 more points!
