Which diagram best illustrates the relationship between the number of cells, tissues, and organs in a complex multicellular organism?

4. 

this diagram clearly shows that all organs are made up of tissues which are in turn made up of cells. thus, the basic unit for both tissues and organs is cells. it also shows clearly that not every cell forms tissues and hence is not necessarily a part of the organ. hence, everything is comprised of cells, from which tissues form consisting of specialized forms and several tissues combine to form different organs.