A skeleton is a structural frame that supports an animal body. There are several different skeletal types: the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside the body, the hydroskeleton, a flexible skeleton supported by fluid pressure, and the cytoskeleton present in the cytoplasm of all cells, including bacteria, and archaea.[clarification needed] The term comes from Greek σκελετός (skeletós) 'dried up'.
This article needs additional citations for verification. (August 2021)