Question

what is diffusion in cell membrane and also explain the diffusion

Answer 1

diffusion is movement of particles from a region of high concentration to a region of low concentration.
In cell CO2 concentration in high and oxygen is low. So CO2 moves into blood and O2 moves into cell. It was an example of simple diffusion.
Note- Diffusion doesn't require energy

Answer 2

Explanation:

Movement of substance from higher concentration to lower concentration.