The fundamental cause of the Peloponnesian War was Sparta's dear and jealousy of the power and wealth of Athens. This caused Sparta to push many city-states to turn against Athens, as well as some citizens of Athens to turn against their own city-state. The Peloponnesian War was fought in three stages or phases as historians like to call them and took place from 431-404 BC.
The United Nations is an international peacekeeping force
Thee answer is D, hope it helped
C) makes sure the branches do not overgrown their original purposes. Explanation:
Checks and balances, principle of government under which separate branches are empowered to prevent actions by other branches and are induced to share power. Checks and balances are applied primarily in constitutional governments.