Final answer:
A common market is an economic agreement between countries that allows free trade within the group and has a common external trade policy. It requires harmony and cooperation among member countries.
Step-by-step explanation:
A common market is an economic agreement between countries that allows free trade in goods, services, labor, and financial capital among its members. In addition to the absence of trade barriers within the group, a common market also includes a common external trade policy. This means that the member countries coordinate and implement a unified trade policy when dealing with countries outside of the common market.
For example, the European Union is a common market where its member countries have eliminated trade barriers among themselves and have adopted a common external trade policy. This allows for the free movement of goods, services, and factors of production within the EU, while presenting a unified trade policy to countries outside the EU.
A common market requires a significant degree of harmony and cooperation among its member countries to function effectively. This includes agreements and coordination on issues such as trade regulations, tariffs, and market access.