The cities of new york, baltimore, and philadelphia began to become wealthy in the late-1600s because of what economic activity? a) trading b) slavery c) rice farming d) tobacco farming

I am gonna say that they grew because of trading.

They made a checks and balance system to equal power within the branches. the "check" meant that one branch would watch one branch and "balance" them if they were too powerful. if you want more info on this, i would just google checks and balance system.

Ibelieve the answer is the  third option, or c.