Explain the process of diffusion and give one example of where this occurs in the human body ?

There are many different types of diffusion that occur in the body however in general they all are the process of a substance moving from an area of high concentration of that substance to and area of low concentration of that substance across a semi-permeable membrane such as the plasma membrane of cells. An example of where this happens is where Oxygen diffuses out of the blood and into the cells of the body lining the capillaries to provide oxygen for respiration.

I've never seen someone post this..

When a virus infects a host cell, it uses the cell's machinery to make copies of its own genetic material in a process called replication. finally, during the process of self-assembly, that protein shell and the copies of the virus's genetic material are assembled into new viruses.