system
A chat on 4chan
human
>gravity
>evolution
I give you even MORE variety 
1-all organisms on earth made out of 20 amino acids, despite 200 amino acids exist in earth alone
2-out of evolution ONLY organisms that has mouth to anus tract development lived on
3- out of all the those organisms only about 1% survived the mega catastrophe 300 million years ago 
Everything on earth today is coming from that 1% mouth to anus tract 20 amino acids organisms
Can you even imagine what would be on earth if organisms made out of 21 amino acids?
Can you even fathom what type of amino acids can be made OUTSIDE of earth? And what those combos will create?!
gpt
ACTHUALLWY
there are a lot primitive animals that still use a singular opening for ingesting food and excreting shit. sea cucumbers, flatworms, etc.
human
Dude even THOSE are mouth to anus
Look it up
Their tract is actually evolved like that
All our tracts are