Would american government be more efficient if power were concentrated within a single branch of government?

Technically, yes.

Since in single power there is noone that could limit the power of the country's leader, all of the leader's decision can be implemented without any resistance. BUT THIS WOULD BE A VERY BAD IDEA, because single branch of the government is basically a dictatorship/tyrannical government.

the united states constitution is the supreme law of the united states. the constitution, originally comprising seven articles, delineates the national frame of government. its first three articles embody the doctrine of the separation of powers, whereby the federal government is divided into three branches: the legislative, consisting of the bicameral congress; the executive, consisting of the president; and the judicial, consisting of the supreme court and other federal courts. articles four, five and six embody concepts of federalism, describing the rights and responsibilities of state governments, the states in relationship to the federal government, and the shared process of constitutional amendment. article seven establishes the procedure subsequently used by the thirteen states to ratify it. it is regarded as the oldest written and codified national constitution in force.

answer; /// i believe that the correct answer is(cognitive revolution);