Gains from trade depend on comparative advantage. Comparative advantage is the ability of a country to produce a particular good or service at a lower opportunity cost than another country. In other words, if a country is able to produce a good or service at a lower cost compared to another country, it has a comparative advantage in the production of that good or service. By trading with other countries, each country can specialize in producing the goods or services in which it has a comparative advantage, leading to a more efficient allocation of resources and increased output. This results in lower prices, increased quantity and variety of goods available, and ultimately higher standards of living for all parties involved.