Unitary monarchies. The United Kingdom of Great Britain and Northern Ireland is an example of a unitary state. Scotland, Wales and Northern Ireland have a degree of autonomous devolved power, but such power is delegated by the Parliament of the United Kingdom, which may enact laws unilaterally altering or abolishing devolution.
A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and expressed in its functioning.