What is the importance of diffusion in living organism

Dear student,
Please find below the answer:

Importance of diffusion:
a) Exchange of gases between blood and individual cells

b) Excretion of waste products by diffusion in the kidneys

c) Opening and closing of stomata in plants

d) Circulation of hormones

e) Transport of glucose and other digested products by blood to individual cells.

Hope this clears your doubt.
Regards.