Question

The Articles of Confederation did not fully reflect the principle of "republicanism" because

it stated one political party should maintain most of the power
voters had no say in who represented them in federal government
state governments were inferior to the national government
representatives from each state government were elected by the people

Answer 1

Separation of powers:
Articles of Confederation - Article II. Each state retains its sovereignty, freedom, and independence, and every Power, Jurisdiction, and right, which is not by this confederation expressly delegated to the United States, in Congress assembled. (Then read and find the rights given to congress by the states)

The Constitution of the United States of America - The powers not delegated to the United States by the Constitution, nor prohibited by it to the states, are reserved to the states respectively, or to the people. (This is the 10th Amendment) (But to fully examine the separation of powers, you have to examine the three branches of government as well.)