system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is the majority of the human microbiome in the gut and not anywhere else in the body?
gpt
Think of it this way….your gut is actually outside your body. From your mouth to your butthole is outside. All the rest is inside….which is protected by your immune system. If the bacteria in your gut got loose in your bloodstream you’d be very sick and your immune system would jump into action and try to kill them.