Answer:
Used an uncrackable code
Explanation:
The Navajo code talkers were part of the marines communications units and used their native language (Navajo) to create messages that were unable to be deciphered.
Answer:
The Soviet Union (USSR)
Explanation:
That country already had the idea to control the Eastern Europe after WWII
The policy of dollar diplomacy was used to justify several interventions by the United States military in Latin America. These events made it clear that the United States was a) willing to exercise its international police power over weaker nations. This happened quite frequently in the years around the Cold War.
I belive it is C. If not, B or D.