Humans and the majority of animal species cannot synthesize essential amino acids (Info: Campbell biology 9th edition). However, meat, eggs, et cetera provide all required essential amino acids. And meat comes from animals.
Main question: So how do these animals we eat get their essential amino acids if they cannot synthesize them either?
My hypothesis: I know they can get it from their diet, but wouldn't it become a never-ending cycle of passing on essential amino acids?
Subquestion if hypothesis is proven: If that is the case, where did these essential amino acids come from?