The two factors that led to the U.S. being considered powerful were:
The economic strength of the US-led to greater respect from leaders of other countries.
The battle of Belleau Wood proved to the world the strength of the US armed forces
During the Battle of Belleau Woods, the U.S. Marines:
Halted a German attack
Sent the Germans retreating
Refused to retreat when the French were retreating and stayed to fight on
This showed the bravery of the American Marine Corps to the world and saved many allied lives as well. This coupled with a strong American economy that provided much supplies for the allied war effort, led many to realize that indeed, America was now a world power.
In conclusion, the bravery and economic strength of the U.S.A. during WWI showed the world that America was a powerful nation.
The fact that U.S. managers' salaries are substantially greater than those of comparable managers in Japan may be related to "<span>d. the greater number of public goods provided in the United States," since CEO salaries are usually tied to performance. </span>