Final answer:
NAFTA, ratified in 1993, includes Canada, the United States, and Mexico, aiming to eliminate trade barriers and enable free trade among these countries.
Step-by-step explanation:
The three countries that are part of the North American Free Trade Agreement (NAFTA), which was ratified in 1993, are Canada, the United States, and Mexico. The agreement aimed to reduce trade barriers like tariffs, taxes, and quotas to facilitate the free flow of goods between these nations. By eliminating these barriers, NAFTA created the world's largest trading bloc in an effort to foster economic growth and compete effectively on the global stage. The process of negotiation and ratification encountered opposition, particularly due to concerns about job losses and environmental impacts; however, supplemental agreements were implemented to protect workers and the environment.