>>97796258>and Amethyst only has a digestive system for fun
all of them have them, they just don't need to use them. Pearl can drink just fine, Garnet does eat too, and they are not the shapeshifting type like Amethyst.
The fact that they have eyes, tongues, teeth and all that crap means they do have internal organs.
Granted, the best way to proof it, for your or my case, is if we were to ever see Peridot eat something, which has not happened yet.