There are three circles the innermost circle indicated the cells middle circle is the tissues and the outermost circle indicated the organs. Multicellular organisms are made up of thousands of different types of cells .Different cells constitute together forma a tissues and different tissues form a organ and different organs together form an organ system. Hence the X labeled circle denotes the tissues.
<span>The cell nucleus contains the majority of the cell's genetic material in the form of multiple linear DNA molecules organized into structures called chromosomes.</span>
