However, it's important to note that the classification of organisms into kingdoms is a somewhat outdated system. Modern classification systems, like the three-domain system, have replaced the traditional five-kingdom system. In the three-domain system, prokaryotes are divided into two domains: Bacteria and Archaea.

So, while "Monera" is still sometimes used to refer to prokaryotes, it's more accurate to say that prokaryotes belong to the domains Bacteria and Archaea.