The regulation of gene expression in eukaryotes is significantly more complicated than that of prokaryotes (bacteria). The simple mechanism of the gene expression is quite simple and direct to the point due to their relatively simple cellular structure (i.e. it has no nucleus). Thus, it is a lot more convenient for prokaryotes to utilize operons as its regulatory mechanism.
Operons ae unique to bacteria, which are single-celled organisms. Why are they not practical foreukaryotic cells found in multicellular organisms like humans?