If you wanted to try and identify or classify archaea or eubacteria, you would study their habitat, study their genetic make-up, study their shape and arrangement, conduct Gram staining, study how they gain energy and nutrients and study how they move. Archaea and eubacteria are genetically different; Archaea have more complex RNA polymerases that contain multiple polypeptides while eubacteria have simple RNA polymerases that contain four polypeptides. Archaea cell walls do not contain peptidoglycan while almost all bacteria cell walls contain peptidoglycan.