Final answer:
Core nations are highly industrialized and dominate global trade, while semi-periphery nations are in transition, with attributes of both core and periphery, and serve as a buffer. Periphery nations provide raw materials and labor to the core but suffer from 'brain drain' and less economic development.
Step-by-step explanation:
The purposes of Core, Semi-Periphery, and Periphery Nations are understood through the core-periphery model which helps to explain the economic and social dynamics of these different categories of countries in the global system. Core nations are highly industrialized, technological, and urbanized. They dominate global trade and politics, are home to large corporations, and rely on the periphery for raw materials and cheap labor.
Semi-Periphery nations are those in transition; they have aspects of both core and periphery nations. These countries, such as Russia, India, and Brazil, play a critical role by stabilizing the global economy through their intermediate economic development, serving as a buffer zone in economic and political terms between the core and periphery.
Periphery nations provide raw materials, agricultural products, and cheap labor to the core nations. The economic activities in these countries tend to be less diversified and are often focused on extracting and exporting resources, resulting in lower wages and less economic development. Additionally, periphery nations experience the 'brain drain' phenomenon, losing educated professionals to core nations due to better opportunities abroad, which can hinder their own development.