what is an amoeba

An amoeba is a type of cell or unicellular organism that has the ability to alter its shape, primarily by extending and retracting pseudopods. Amoebae do not form a single taxonomic group; instead, they are found in every major lineage of eukaryotic organisms. Amoeboid cells occur not only among the protozoa, but also in fungi, algae, and animals. Amoebas are unicellular organisms that can be found in water bodies such as ponds, lakes, and slow-moving rivers. They are characterized by the formation of pseudopods that can be extended and retracted as the cell moves. Amoebas are eukaryotes, and their single cells possess certain characteristic features such as a cell membrane and a nucleus. The term "amoeba" is used to generally refer to any cell that exhibits an amoeboid movement. The most extensively studied species of amoeba is Amoeba proteus, which is found in terrestrial as well as aquatic habitats.