What was the reason for the Mexican-American war?

Iwill be giving 15 points to whoever answers the concept of checks and balances means that each branch of governmenta. has its own powers and responsibilitiesb. is clearly described in articles of the constitutionc. has the ability to correct the other branches in case of an errord. is set up so that in case of constitutional crisis, the governement will continue to operate

Is the idea of containment relevant to american foreign and policy today why or why not

Which fact would this be, and how might you verify the truth?