Which of the following policies did the united states pursue with regard to china in the 19th century?

roosevelt corollary

pingpong diplomacy

monroe doctrine

open door policy

federal power is further limited with a system of checks and balances that gives each branch of government a measure of power over the others.

explanation:

1) the answer is b

senators serve a six-year term; representatives serve a two-year term, making them more responsive to (and responsible for) voter confidence.

2) the answer is d

to serve as president, one must:   -be a natural-born u.s. citizen of the united states;   be at least thirty-five years old;   be a resident in the united states for at least fourteen years.

3) the answer is a

ella,because it is constitutionally eligible

4) the answer is c: the u.s president