Difference between Unicellular and Multicellular organisms

Unicellular Organism 

Multicellular organism

Has only one cell that performs all body functions

Have multiple cells to perform different body functions

Complete Cell body is in contact with the external environment

Only outer cells of the organism are in contact with the external environment

Usually have short lifespan 

Have longer lifespan 

Injury leads to death of the organism

Injury to one cell does not lead to death of the organism.

Reproduce mainly asexually

Reproduce sexually as well as asexually

For Example - Bacteria , Yeast etc

For Example - Humans , plants , animals etc