Division of responsibilities into distinct branches to limit any branches from exercising the core functions of another is _______?

The correct term is "separation of powers." Separation of powers is a system of government in which power is divided among different branches, such as the legislative, executive, and judicial branches. The purpose of this system is to prevent any one branch from becoming too powerful or abusing its authority. In this system, each branch has its own distinct responsibilities and powers, and these powers are carefully balanced to prevent any one branch from becoming dominant. For example, the legislative branch is responsible for making laws, the executive branch is responsible for enforcing laws, and the judicial branch is responsible for interpreting laws. The separation of powers is an important principle in many modern democracies, including the United States, and is intended to promote accountability, prevent abuse of power, and ensure that government serves the interests of the people.