Democratic Politics (NTSE/Olympiad)
It is a system of government in which the power is divided between a central authority and various constituent units of the country. Usually, a federation has two levels of government. One is the government for the entire country that is usually responsible for a few subjects of common national interest. The others are governments at the level of states that look after much of the day to day administering of their state. Both these levels of governments enjoy their power independent of the other.
Unitary System :
There is only one level of government or the sub units are subordinate to the central government. The central government can pass an order to the provincial or the local government. But in a federal system, the central government cannot order the state government to do something. State government has powers of its own for which it is not answerable to the central government.