eros angel boy and skeleton material with dark background

>For other uses, see Skeleton (disambiguation). In biology, the skeleton or skeletal system is the biological system providing support in living organisms. (By extension, non-biological outline structures such as gantries or buildings may also acquire skeletons.)Skeletal systems are commonly divided into three types - external (an exoskeleton), internal (an endoskeleton), and fluid based (a hydrostatic skeleton), though hydrostatic skeletal systems may be classified separately from the other two since they lack hardened support structures. Large external skeletal systems support proportionally less weight than endoskeletons of the same size, and thus many larger animals, such as the vertebrates, have internal skeletal systems. Examples of exoskeletons are found in arthropods, shellfish, and some insects: the skeleton forms a hard shell-like covering protecting the internal organs. See more at Wikipedia.org...

tremely Reliable Operating System) is an operating system developed by the University of Pennsylvania and the Johns Hopkins University. It is mostly used as a research project. As of 2005, real world usage is unknown, and development has stopped. Interesting features include automatic data and process persistence, real-time support, POSIX compatibility, and capability-based security. See more at Wikipedia.org...