>>11250091Environmental pathogens build up under your finger nails and in belly button and both environments are quasi anerobic,
Dangerous anerobic pathogens and regular aerobic pathogens are cultured there, externally from your precious and fragile internal system,
The pathogens are safely compartmentalized and benign,
The culture is right on top of a capillary filled membrane, harmless amounts of pathogens pass through the membrane.
Your immune system develops resistance to environmental pathogens ;)
This is aquired immunity, which is different to genetic immunity you inherit and immunity from actual pathogen attacks you have had.
Children eating dirt and licking things is another mechanism to acquire.
Oh and eating boogers lol.
It's all there in the DNA people.
