John Brown was seen as a hero
D. Trade can keep countries from specializing in producing certain goods.
The growth of the railroads had a major effect on supply and demand for natural resources in the US, since it made it much easier and cheaper to transport these resources from place to place, which increased their demand and thus their supply.
George Washington warned against in his Farewell Address :
( D ) Political Party Infighting.
<em>George Washington advised American citizens to view themselves as a cohesive unit and avoid political parties ínfighting</em> and issued a special warning to be wary of attachments and entanglements with other nations.
I believe you are referring to the evacuation of Saigon (Fall of Saigon) on April 30, 1975. If so, the correct answer is c. The U.S. evacuated Vietnamese whose lives would be in the greatest danger if they were to be left behind.