Many native Americans were forced into labor on roads
During the 1980s, the United was deeply involved in Latin
America because the growing problem of Communists insurgents in the region
particularly in El Salvador, Guatemala and Nicaragua. The Cold War was still on and the U.S. feared
that Communism would take root in these areas and might threaten if they
continue unabated.
The bering strait is the land bridge
The answer would be #3
Due to lack of trees to use for building a cabin, many of the prairie homes were made of sod.