Multicellular organisms are made up of cells most of which are specialised to prefor, specific functions. this occurs in tissues and organs.
An organ is a collection of different tissues which preform a specialised function. e.g. the heart.
What is the cost of Specialisation?
the specialised become totally dependant on the activities of other cells
An Acellular Organism
Is a multicellular organ or organism without division into separate cells.
Plant and Animal cells