Outline the need for communication systems within
External environmental changes are changes in the external environment which
can cause stress. it may change slowly so there will be a gradual response. it
may be a quick change so a rapid response is needed.
Internal environmental changes are that the environment of internal cells is that
they are protected by epithelial cells and they are bathed in tissue fluid. the
activities of cells alter their environment for example, by releasing toxic products
that need to be removed. the co-ordination of activites of organs are that there are
groups of specialised cells to form tissues and organs. The cells monitor the blood
and can release a substance into the blood to remove certain substances.