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.
homologous chromosomes ... sister chromatids
Any change or random error in a DNA sequence is called a mutation.
Im totally guessing here but im gonna go with choice b
