Impeachment is a constitutional mechanism used in many democratic systems to hold public officials accountable. It involves a formal charge of misconduct, such as treason, bribery, or other high crimes, brought by the legislative body. If the official is convicted during the subsequent trial, they are typically removed from office. This process serves as a critical check and balance against the abuse of executive or judicial power.

The principle of checks and balances in the U.S. Constitution is designed to prevent any single branch of government from becoming too powerful. By granting each branch—legislative, executive, and judicial—specific powers to oversee and limit the others, the system forces these three organs to cooperate and compromise to ensure the effective functioning of the government and the protection of democratic principles.

The United States governmental system is famously built upon the doctrine of separation of powers, as articulated by Montesquieu. The U.S. Constitution explicitly divides authority among the legislative, executive, and judicial branches, each with distinct powers and a system of checks and balances. This structural design was intended to prevent the concentration of power and ensure that no single branch could dominate the others, making it the quintessential model of this political theory.

The name most associated with the doctrine of the separation of powers is that of Charles Louis de Secondat, Baron Montesquieu. His influence upon later thought and upon the development of institutions far outstrips, in this connection, that of any of the earlier writers we have considered. His work, 'The Spirit of the Laws', remains the definitive text on the necessity of dividing government power to prevent tyranny.

Constitutional government relies on the separation of powers to prevent tyranny. By distributing authority across distinct branches—executive, legislative, and judicial—the system ensures checks and balances. Combining these powers into a single entity or individual violates the core tenet of constitutionalism, as it removes the necessary oversight required to protect individual liberties and maintain the rule of law.

The presidential system, most notably in the United States, is built upon the constitutional doctrine of separation of powers. This structure ensures that the executive, legislative, and judicial branches operate independently with distinct functions and checks, preventing the concentration of power in a single entity, unlike parliamentary systems where the executive is drawn from and accountable to the legislature.

The separation of the judiciary from the executive is a fundamental principle of constitutionalism. By ensuring an independent judiciary, the state prevents the executive branch from exercising arbitrary power. This independence allows the courts to act as impartial arbiters, protecting citizens' fundamental rights against potential encroachment or abuse by government authorities.

The source identifies 'authoritarianism' as the answer, which contradicts standard political science definitions of US-style pluralist democracy. The US system is defined by the separation of powers and checks and balances. This answer key appears factually incorrect based on established democratic theory.

The term 'co-ordinate' implies that both houses of a legislature possess equal or balanced authority in the legislative process. While many systems have asymmetric bicameralism, the concept of co-ordinate powers describes a system where both chambers must agree for legislation to pass, ensuring checks and balances between the two bodies.

Under the rules of procedure for the Lok Sabha, the Speaker nominates a panel of chairpersons from among the members. This panel consists of six members who can preside over the House in the absence of the Speaker or the Deputy Speaker. This ensures the continuity of legislative proceedings and maintains the orderly conduct of business within the chamber during sessions.