Bacteria They are formed by a single rudimentary cell. They have no nucleus or plastids, but chromatin. Some have assimilators pigments. They are on earth, water, and air, and can generally move. They may be causing disease and therefore are called pathogens. Those that do not cause disease are called saprophytes. In some cases, they are even useful, as in digestive processes or synthesis of vitamins. By the way, they are called coconuts when circular; bacilli if they have the form of rods;…