Why did the framers of our country build in a system of checks and balances into our goverment

Which of the following factors would be a likely reason for low population density

Which of the following is an example of the pull factor known as economic migration? a. better educational opportunities pulling people towards a new country b. mexican laborers entering the us to work in agricultural jobs c. joining family members that are already in a new country d. crop failures driving people away from their country i am unsure on this question, i was thinking b? but i could be wrong.

Full-service brokerage firms a. have lower commissions. c. provide no investment advice. b. offer portfolio management. d. teach you how to do market research.