Different domains of life are characterized by distinct cellular structures and biological functions. The three primary domains are Bacteria, Archaea, and Eukarya. Bacteria and Archaea are prokaryotic, lacking a defined nucleus, while Eukarya consists of eukaryotic cells, which have organized nuclei and membrane-bound organelles. Furthermore, differences in genetic material, cell wall composition, and metabolic pathways help distinguish these domains. These differences underscore the vast diversity of life forms on Earth.