Why have some historians rejected the labels bc and ad as labels for periods in world history?

He u.s. constitution (1787) establishes a national legislature with powers to “create national law”, a national executive with the power to “enforce national law”, and a national judiciary branch with the power to “interpret national and state policies” to see whether or not they violate the national constitution. this term describes the division of governmental authority into semi-independent bodies?

How did the united states surprise other delegates at the washington naval conference in 1921

What kind of non military support did u.s give to europe