Before international trade, each governmental unit would practice isolationism, or providing for its people with its own resources. Why is global trade beneficial?

What is The International Monetary Fund, and how does it facilitate world trade?

How does allowing distribution of goods and services through free trade improve efficiency in production? States will regulate more effectively. People won't need to work as much. It is not true that trade promotes efficiency. Entrepreneurs will be rewarded by improving products and methods.

In practice do the policies of countries around the world reflect a commitment to free trade?