What distinguishes the kingdom Monera from others?

The kingdom Monera is distinguished primarily by the fact that its members are unicellular organisms. This means that all organisms classified under Monera consist of a single cell, which is a defining characteristic of this group. Additionally, Monera includes prokaryotic organisms, which are characterized by the absence of a true nucleus and the fact that their genetic material is not organized within a membrane-bound nucleus, as seen in eukaryotic cells.

In contrast to other kingdoms, such as Protista, Fungi, and Plantae, which can include multicellular organisms, Monera specifically refers to unicellular forms, including bacteria and archaea. This defining feature is crucial in differentiating Monera from other biological classifications. The presence of a nucleus, multicellularity, and cell walls made of cellulose are properties that define or relate to other kingdoms, thereby further clarifying why the unicellularity of Monera is its key distinguishing trait.