How do countries and businesses participate in international trade?

"Absolute advantage is the situation when a country can produce and sell a product at a lower cost than any other country or when it is the only country that can provide the product. Buy-national regulations are government rules that give special privileges to domestic manufacturers and retailers. Contract manufacturing is the practice in which a foreign firm manufactures private-label goods under a domestic firm’s brand name. Countertrade is a form of international trade in which part or all of the payment for goods or services is in the form of other goods and services. Dumping is the practice of charging a lower price for a product in foreign markets than in the firm’s home market. An embargo is a total ban on imports or exports of a product. Exporting is the practice of selling domestically produced goods to buyers in another country, while exports are goods and services produced in one country and sold to other countries. Free trade is the policy of permitting the people and businesses of a country to buy and sell where they please without restrictions. A free-trade zone is an area where the nations allow free, or almost free, trade among each other while imposing tariffs on goods of nations outside the zone. An import quota is a limit on the quantity of a certain good that can be imported. Imports are goods and services that are bought from other countries."