Question

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

Answer 1

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Multi-cellular organism’s like humans have very big body and require a lot of oxygen to diffuse into body quickly in order to meet the oxygen requirement. Diffusion is a slow process which will take a lot of time to circulate oxygen to all the body cells. Because of its slow nature diffusion is insufficient to meet the oxygen requirements of multicellular organisms like humans.

Answer 2

Answer:

HI!

Cells in multicellular organisms are not in direct contact with the environment.

So, diffusion is insufficient to meet the oxygen requirements in multicellular organisms.

Whereas, single celled organisms like amoeba has whole body in the direct contact in the environment.

This is why oxygen requirements in unicellular organisms is fulfilled sufficiently.

Humans also under multicellular organisms, this is why they need organs like lungs to satisfy their oxygen requirements.

Similarly, fishes have gills to satisfy their oxygen requirements.