I want to know the answer to the following question:
What did Aristotle add to Plato's work?
All the background I'm provided with is that "The antecedents of European politics trace their roots back even earlier than Plato and Aristotle, particularly in the works of Homer, Hesiod, Thucydides, Xenophon, and Euripides.". Is that enough to answer the question?
Answer: no