International Trade

Trade is efficient because those producers and nations which are “better” at producing a good or service can focus on that and export it to other countries.
What they are “better” at is their area of comparative advantage and to focus on this area means to specialise in it.

Absolute Advantage	Having greater productivity, or producing more with fewer resources
Comparative Advantage	Having a lower opportunity cost, or having less to loose by producing something
Specialisation	Producing goods/services in which the opportunity cost is the lowest – which is necessarily inverse for the other actor. Specialisation enables trade and increases total output and efficiency
Protectionism	Restriction of trade through tariffs and quotas. Reduces total gains from trade, but there are winners and losers