Final answer:
Dependency theory explains global inequality by describing how high-income core nations exploit middle-income semi-peripheral and low-income peripheral nations, creating a cycle of dependence that inhibits the peripheral nations' economic growth.
Step-by-step explanation:
The theory that describes a world divided between a dominant core and a dependent periphery as a result of global capitalist expansion is known as dependency theory. This theory suggests that global inequality is chiefly caused by the exploitation of semi-peripheral and peripheral nations (middle-income and low-income nations) by core nations (high-income nations). Dependency theory posits that this creates a cycle of dependence whereby peripheral nations cannot achieve stable and consistent economic growth. They rely on the economic stimulus from core nations and access to the global economy, which benefits the core nations and maintains their dominant status. The core nations, including institutions like the World Bank, also influence which countries receive loans and the conditions tied to those loans, further perpetuating global stratification.