Do you reject St. Thomas's Aristotelian biology and physics, or both?

I take Thomas one thought at a time. Most of what he says I agree with, like the five proofs of God, but I do not buy the Aristotelian idea that everything is substance and accidents; that is a metaphysical notion with no real proof. Thomas thought gold was a pure substance that could not be subdivided, but we found out five hundred years later that gold is made of atoms and quarks, and that adding an electron and a couple of neutrons turns gold into platinum, and removing them turns it into mercury. That is the periodic table, and it shows gold is not a substance in his sense. As for Aristotle's biology, it was in its infancy; biology is based on complex carbon chemistry Aristotle had not the first clue about, so no, I will not put my confidence in his biology.