Can prokaryotes be multicellular?

Yes, prokaryotes can be multicellular. While prokaryotes are typically single-celled organisms, some species have evolved forms where multiple cells aggregate and cooperate. These multicellular prokaryotes are often referred to as "multicellular aggregates" rather than true multicellular organisms because they lack the complex differentiation and specialization of cells seen in multicellular eukaryotes. Examples of multicellular prokaryotes include cyanobacteria and myxobacteria.

Cyanobacteria can form colonies where multiple cells aggregate and perform specialized functions such as nitrogen fixation or photosynthesis. Myxobacteria are known for forming multicellular structures called fruiting bodies, where cells cooperate to move as a unit and undergo complex developmental processes.

These examples show that while prokaryotes are mostly single-celled, multicellular-like behaviors and structures can emerge under certain conditions, demonstrating the adaptability and diversity of microbial life.