Propose an explanation for why operons evolved in prokaryotes. what advantage do organism have when they group genes together with regulatory

This is because the genes that make up an operon are related in function since they transcribe for the different subunits of a functional protein or enzyme. Operons, therefore, make regulation of functional proteins more efficient since its an all or none type of regulation. No subunits will be transcribed independently and not get involved in making a functional protein (due to lack of other subunits that are not yet transcribed) hence no wastage.