Why is diffusion insuffient to meet the oxygen requirment or multicellular organism like process?

Why is diffusion insuffient to meet the oxygen requirment or multicell

1.	Why is diffusion insuffient to meet the oxygen requirment or multicellular organism like process?
Answer» Diffusion is insufficient to meet the oxygen requirement or multicellular organism life process as it has to diffuse from each cell to other between less number of cells this method would be sufficient but due to innvolvement of millions of cells in a life process this method will appear to be insufficient. Diffusion is insufficent to meet the oxygen requirment of multicellular organism like process because in multicellular organism all the cell may not be indirect contain with the surrounding enviroment;