Answer:
Binding of RNA polymerase to consensus sequences on DNA.
Step-by-step explanation:
A σ factor or sigma factor is known as a protein that is needed for the initiating of the transcription process in bacteria. It is known as a bacterial transcription initiation factor that helps to enable specific binding of RNAP (RNA polymerase) to gene promoters.
The σ factor, together with RNA polymerase, is called the RNA polymerase holoenzyme complex (which is required for the initiation of the transcription process). The σ subunit of prokaryotic RNAP consensus sequences found in the promoter region which is present in the upstream of the transcription start sight. A promoter is known as a DNA sequence where the transcription machinery binds and starts the transcription process.