Unicellular organisms are composed of a single

Simple body organization 

A single cell carries out all necessary life processes

The total cell body is exposed to the environment 

Division of labour is at the organelle level 

Includes both eukaryotes and prokaryotes   

A lifespan of a unicellular organism is usually short 

 Multicellular Organisms

 Multicellular organisms are composed of more than one cell

Complex body organization

A single cell carries out all necessary life Simple body organization
 

processes Multiple cells perform different functions

The total cell body is exposed to the environment Only the outer cells are exposed to the environment

Division of labour is at the organelle level Division of labour is at cellular, tissue, organs and organ system level

Includes both eukaryotes and prokaryotes Includes only eukaryotes

A lifespan of a unicellular organism is usually short Multicellular organisms have a comparatively longer lifespan

Injury to the cell leads to the death of the organism Injury to a cell does not cause the death of the multicellular organism