why do countries practice international trade

好巧哦，我历史老师正好要我写这篇作文！（本人在美国）
Not every country has the same raw materials and natural resources. International trade makes it possible to get things one country lacks from another country.International trade also creates market and increses for finished products. Economically, this practice is called interdependence. Countreis denpend on one another to prosper. Moreover, this interation between different cultures of different countries creates a cultural diffusion. Ideas and beliefs get around as trade goes on.
For example, in the ancient times, the Silk Road serves as a best way to carry ideas, beliefs, and goods betwen countries of the Middle East, Europe and China. Buddhism, Christianity, Islam were spread this way.

为什么国与国之间实行世界贸易？