I think the answer is naturally acquired active immunity..also depends on which disease
I guess that is:
Within the capillaries of the lungs, gases are exchanged by diffusion; O2 diffuses from the alveolus to the bloodstream and CO2 diffuses from the bloodstream to the alveolus.
For the answer to the question above, I believe that the demographics are exhibiting and prioritizing the stores who have a more traffic and they exhibit more loyalty after the store was visited.
Customers like us are more likely to buy which a physical store can be visited.
Lichens are prominent on rocky shores.
