Bacteria and Archea are two domains of life (Eukarya is the third) which share some characteristics. Both are microorganisms with almost the same shape, size, and appearance. They also share the structure of the cell-prokaryotic cell. This means that Archea and Bacteria are single-celled organisms that do not have a nucleus or membrane-bound organelles. Reproduction of both domains is performed by asexual reproduction with the process of binary fission, budding or fragmentation. Sometimes habitat of Archea and Bacteria is the same, like those in hot springs.