Final answer:
A free trade area is the form of economic cooperation that allows countries to eliminate internal barriers to trade while maintaining independent trade policies with non-member countries.
Step-by-step explanation:
The form of economic cooperation that calls for countries to eliminate all internal barriers to trade among themselves even while maintaining independent trade policies vis-à -vis third countries is known as a free trade area. In a free trade area, member countries can trade with each other without imposing tariffs or quotas, but they can still have their own trade policies with non-member countries.