system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do our noses clog up with snot/bogies when they are an essential airway?
gpt
The aren't an essential airway, they are one of two in a wonderfully redundant system.

They clog up because they aren't a perfect design (damn you, designer!).  They are an intake mechanism that is _way better_ to get infected than your lungs.  Don't think of it as the blocking of a key airway, think of it as the clogging of your filter that protects all your REALLY key systems.