Answer:
The 26 states in Switzerland once formed an alliance known as a confederation. During that period, the major share of power rested in the state government.
Explanation:
Answer: Swinging its industrial might and vast manpower behind France and Britain against Germany and its allies on April 6, 1917, the United States tipped the balance of the conflict and marked its own emergence as a global power
Explanation:
I believe it is the 'domino theory' as one country falls then pushes the next to fall and so on and so forth. Just like dominos.
I think it was the decimal system and concept of zero
