Question

why we can say that spreading of virus by sneezing is a diffusion process

Answer 1

Diffusion is the movement of particles from a region of higher concentration to a region of lower concentration. that is why we can say that spreading of virus by sneezing

Answer 2

Diffusion : movement of a substance from higher concentration area to lower concentration area. When we sneeze, the saliva particles are in a concentrated state. They start moving in other areas (where they are not concentrated, that is, lower concentration area.) thus, this is an example of diffusion of saliva particles from higher concentration area to lower concentration area.