R-RNA is mainly produced in -

B i.e., NucleolusThe sigma (a) subunit (factor) enables RNA polymerase to recognize promoter regions on DNAQ.Like DNA polymerase, RNA polymerase uses nucleoside triphosphate as substrates & releases pyrophosphate each time a nucleoside monophosphate is added to growing chain. And as with replcation, transcription is always in 5' -s 3'direction. However, incontrast to DNA polymerase, RNA polymerase (both in eukaryotes and prokaryotes) does not require primer and has no known proofreading activityQ.