Either C or D
The Aztecs sure as hell didn’t welcome any foreigners, and smallpox was brought from Europe
Yea or no pick one and then answer the question
It protected the United States from competitors located in foreign countries.
James Madison, John Jay, and Alexander Hamilton.
Answer:
C. Trench warfare
Explanation:
A's incorrect as alliances have existed for thousands of years
B's incorrect as an infantry charge's greatest weakness is the machine gun for obvious reasons
D's incorrect as both sides had machine guns, and was not the reason for victory.
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This leaves C, which makes sense as troops would be forced to hide on lower ground due to the deadliness of machine guns