<prompt> Micro RNA is transcribed bya RNA polymerase Ib RNA polymerase IIc RNA polymerase IIId DNA Polymerasee Droshaabadbece  <response>: Micro RNA mi-RNA are typically 21-25 nucleotides in length and are generated by nucleolytic processing of the products of distinct genestranscription units. These precursors are single-stranded but have extended intramolecular secondary structure.Most mi-RNA are processed from RNA polymerase II transcripts of severed hundred to thousands of nucleotides in length called Pri-miRNA primary transcript. Within these long transcripts are sequency that fold into a hairpin structure. A nuclear RNAase specific for dsRNA called Drosha acts with a nuclear ds-RNA binding protein called DGCR in human Pasha in Drosophila and cleaves the hairpin region out of long precursor RNA generating a pre-miRNA. 