Which of the following is an example of the principle of checks and balances?
a. presidents can veto an act of congress
b. members of congress have the power to raise their own salaries
c. federal courts have the power to veto federal laws
d. presidents can appoint officers of the armed forces

i believe that the answer to the question provided above is that the role of campaign committees is to act as a bridge between state and local campaigns.

productive most commonly means: achieving or producing a significant amount or result.

explanation:

productive can also mean:

these depend on how the word productive is used. most likely productive will mean   achieving or producing a significant amount or result.