The ability and tendency of certain systems to maintain a
relatively constant internal state in spite of changes in
external conditions; this ability is achieved by the presence
of feedback mechanisms which can adjust the state of the
system to compensate for changes in the state caused by the
external environment. It is exemplified in homeothermal
biological systems, such as animals which maintain relatively
constant blood temperature and composition in spite of
variations in external temperature or the composition of the
food ingested.