What explains why nations must trade?

The rationale behind why nations must trade lies in the uneven distribution of resources across different countries. No single nation possesses all the resources—such as raw materials, technological capabilities, or agricultural products—required to meet the needs and desires of its population.

This scarcity necessitates trade, as countries can obtain goods and services that they are unable to produce efficiently or at all due to geographic, climatic, or economic factors. For example, a nation with abundant natural resources may not have the technology to refine these materials into products, while another nation may have advanced technology but lack sufficient resources to manufacture goods independently. By trading, countries can specialize in what they do best, leading to increased efficiency and overall economic benefits.

The other options do not accurately reflect the reasons for trade. Nations are often not entirely self-sufficient and rely on trade to access essential goods. Trade is beneficial to countries of all sizes, not just large ones, and most countries do not have all the resources they require, which further emphasizes the importance of trading with others.