(1) $RNA$ polymerase allows the transcription of structural genes to synthesize a polycistronic $ m-RNA$
(2) Many genes have stretches of notrogen bases that code for amino acids and are called 'exons'
(3) Heterogenous nuclear $RNA \: ( hn\: RNA) $is synthesized from split genes
(4) The bases that do not code for amino acids are called 'introns'
