Subduction Zone
Veteran Member
Biochemists are still undecided on whether the amino acids already exist on earth, or whether they came from meteorites or comets.
The evidences for both are here and now, but whether the ultimate origin of amino was terrestrial or extraterrestrial, we may never know.
It could even be a mixture of the two. The Miller -Urey experiment showed that they could have arisen naturally on the Earth. Then when the atmosphere used was doubted it was done again, and again, and again. They kept coming up with amino acids. Meanwhile as you pointed out separately they have been found in meteorites.
Now the work that is done is to see how it may have happened. Currently it sounds like there could be more than one pathway and since there is no record of the development of life we may never know exactly how it happened.