What started the greco-persian wars?

They started because the Persian Empire expanded into Ionia where there were several Greek colonies. The colonists sent back to Greece for help. The Athenians sent a few ships to help the colonists, but the cities were taken any way. To put the mainland Greeks in their place, the Persians sent a small force to punish the Greeks. So begins the battle of Marathon.

your answer to this question is true hope this

a system of cooperative federalism emerged, as the powers of the federal government expanded.