Italy never had a strong feudal system. why did this make it easier for city-states to develop?

Feudal systems are arcane and hierarchal and actually stunt development. The city-states were free of the loyalties and hierarchies of feudal states. They were dynamic sites for entrepreneurship.

Explanation: City-states were the precursors of modern empires

interdependence is when all participating groups and individuals depend on each other. if you depend on one anothers goods, you end up trading in order to get the items you're looking for. (for ex: if i have food and you have water, we trade in order to depend on each other to live)

the tariff was created to protect industry in the northern part of the united states. industries in the north were being driven out of business by imported goods that were priced at a low rate. the goal was to protect these industries   by taxing the goods.