Countries such as Sweden (A. trade B. import C. buy) natural resources such as wool and zinc that are ( A. scarce B. abundant C. renewable) in that country with countries that need them.

The correct answer is C. The historical event that explains the large number of refugees to the United States arriving from Bosnia-Herzegovina, Serbia, and Montenegro from 1999 to 2001 is the break-up of Yugoslavia into smaller independent nations.

Explanation:

The break up of Yugoslavia is a generalized name for the events of 1991-2008, as a result of which the former Socialist Federal Republic of Yugoslavia (SFRY) was divided into six independent countries and one partially recognized state. The process of state collapse dates back to 1991-1992, when four of the six republics (Slovenia, Croatia, Bosnia and Herzegovina and Macedonia) separated from the SFRY. At that time, UN peacekeeping forces were introduced into the territory of Bosnia and Herzegovina and then the autonomous region of Kosovo.  

In 1999, the United States and its allies conducted a military operation in the autonomous region of Kosovo, which fell under the UN protectorate. On June 3, 2006, with the withdrawal of Montenegro, Yugoslavia finally ceased to exist.