Which governing principle is best reflected by the three branches of the federal government created by the constitution

Separation of powers

Explanation:

The governing principle of separation of powers is firmly entrenched in the constitution. It is a governing principle that ensures checks and balances in government.

The federal government is composed of three branches which are; the executive, the legislature and the judiciary.

All these arms of government work together to ensure the smooth operation of the country's democracy by ensuring that each arm of government exercises its powers according to the provisions of the constitution.

The term "agree to disagree" or "agreeing to disagree" is a phrase in English referring to the resolution of a conflict  where by all parties tolerate but do not accept the opposing position(s).

Let me give you an example:
If say that the sea is blue-ish and you say its green-ish. Neither of us are prepared to alter our belief, so we agree to disagree.
I hope it helped!! :)