There are five (5) levels of cell organization recognized by biologists. They are cells, tissues, organs, organ systems and organisms. These are applicable to multicellular organisms though as they are needed for the cells to sustain their functions alone and eventually coordinating with one another. Cells are the basic unit of life, when grouped together, they are tissues. When tisuues are grouped together, they are organs and organ systems comprises of two or more organs to function and overall, creating an organism.