Answer:
See Explanation Below
Step-by-step explanation:
A: The Domino theory was the thought of If one country falls to Communism then the others will fall .
B: The overwhelming threat of The Red Menace was so immense that the US went to help the South Vietnamese fight off their Communist Enemy. If we were to stay neutral Vietnam would fall (it did anyways) and the surrounding countries would fall to Communism as well.
C: They assisted in many ways, from sending troops, military supplies and funding for the war effort. They also helped train the soldiers in combat.
D: The Vietnam war was something unlike the US had ever seen, Guerilla fighting like no other, it's almost reflective of the US revolutionary war. The Vietnamese fought so hard because they fought for their homes. In the end North overtook the South.