Question

why diffusion insufficient in humans

Answer 1

The oxygen requirements of an animal cannot be met by the process ofdiffusion as diffusion is a very slow process. To overcome this, multicellular organisms have specialized cells and tissues for performing various necessary functions of the body such as intake of oxygen and food.

Answer 2

because there are specific organs for specific functions eg .. for respiration lungs are included and for digestion stomach and small intestine is required so...bht in unicellular it is possible because they r single celled ....hope it helps dude