Why is diffusion insufficient to meet the oxygen requirements of multi- cellular organisms like humans?

Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?

Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like ?

Why is diffusion insufficient to meet the oxygen requirement of multicellular organisms like humans?

Why is diffusion insufficient to meet the oxygen requirements of multicelluar organisms like humans?

(a) Why is diffusion insufficient to meet the oxygen requirements of large multicellular organisms like humans? (b) What type of arrangement exists in the bodies of large animals to meet their oxygen requirements adequately ? (c) What advantage a terrestrial animal has over an quantic animal with regard to obtaining oxygen for respiration?