What type of organisms are classified as bacteria?

Bacteria are classified as single-celled organisms, which is the defining characteristic of this type of life form. These microorganisms consist of a single cell and are prokaryotic, meaning they do not have a nucleus or other membrane-bound organelles. This distinguishes them from multi-cellular organisms, which are made up of multiple cells and often have specialized structures and functions. Viruses, on the other hand, are not classified as living organisms since they require a host cell to replicate and do not have cellular structures. Fungi are also distinct because they are multicellular (with some exceptions, like yeast) and belong to a different kingdom of life altogether. Thus, the classification of bacteria as single-celled organisms is accurate and aligns with biological taxonomy.