Question

why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like human ? ​

Answer 1

Answer:

Because all the human cell are not in the direct contact with the environment so may billions of years to meet the oxygen requirement in multi cellular organism like human

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Answer 2

Answer:

Unlike the unicellular organisms, the multi-cellular organisms have complex body structures with specialized cells and tissues to perform various necessary functions of the body. Since these cells are not in direct contact with surrounding environment so, simple diffusion cannot meet the oxygen requirement of all these cells.