This document discusses trading partners and interdependence. It defines a trading partner as two or more participants in an ongoing business relationship, and a business relationship as an association between companies entered into for commercial purposes through a legal contract. Countries trade more when they have differences in climate, labor, capital, and innovation abilities. Interdependence describes how trading partners rely on and influence each other. For example, China and the US influence each other's economies. The document then discusses types of interdependence and China and North Korea's trading relationship.