Answer: Option (2) and (3)
Improve accountability of government officials, thus leading to more efficient policies.
it enhance government ability to make effective decisions quickly.
Explanation: when governmental power is shared or dispersed among the states you directly allow for more efficiency within the system by giving the state the right to solve some of their problem. To have a national solution to a problem that ensue might result to contrary results among the states, but allowing each state to seek for solutions and make policies best for them, will result to more efficiency.
Many layers of the federal government is the United State allows different policies to be tried by the states, and the ones found most effective at solving problem can then be implemented in other state or even at the national level as the case may be.
