All political powers in a state are concentrated at the central level under what form of government

The answer to this question is the unitary government. A unitary government is a form of government where in the state is governed by a single power in which the central government have the highest power and other divisions power was only designated or assigned only by the central government. Also in this kind of government, most of the countries used this system. Countries with unitary government are United Kingdom, Ireland, France, Bolivia, Canada, Italy, Philippines, Mexico, Russia, Iceland, etc.