Yes, only single celled organisms, as prokaryotes do, but some bacteria form colones with limited specific cell functions, some signal to each other and aggregate into fruiting bodies and form spores to survive hard conditions and many form biofilms and stromatolites.
So, a single cell can do many things as life is more complicated than simple definitions would have you believe.
Bacteria
The kingdoms eubacteria and kingdom archaebacteria are bacteria kingdoms, which are unicellular.
They are unicellular organisms. Bacteria, protozoans and certain fungi are unicellular.
The kingdom that has only one cell and lacks a nucleus is Monera. Monera includes unicellular prokaryotic organisms such as bacteria, which have a simple cell structure without a membrane-bound nucleus.
There is no single kingdom that is unicellular. All prokaryotes (organisms with no cell nucleus) are unicellular, and they belong to two domains, bacteria and archaea. Eukaryotes, or organisms with a cell nucleus, are divided into four kingdoms, plants, fungi, animals, and protists (although recently scientists began to reclassify protists into multiple separate kingdoms). In each of the fungi and protist kingdoms, there are a variety of members that are unicellular, and also some members that are multicellular. Animals and plants are always multicellular (except possibly one animal group called Myxozoa).
The domains Bacteria and Archaea are composed of only unicellular organisms. These organisms are prokaryotic and lack a true membrane-bound nucleus in their cells.
Bacteria and Archea (Archbacteria)
Protista
A living organism that consists of only one cell is called a unicellular organism. Some examples include bacteria, algae, and protozoa.
Not all the unicellular organisms have Ribosomes, but most of them Do.Dna Is an integral part of multicellular organisms, but not all unicellular have DNA.It is believed that first living cells were bacteria, although other unicellular organisms lived for millions of years before them.
you mean unicellular organism then we have following organisms which are formed of only one cellAmoebaParameciumEuglenaPlasmodium etcthey all are unicellular eukaryotic organisms and prokaryotic organisms include bacteria and cyanobacteria
the more classification levels that two organisms share