Answer : 2. "Federal character of government "
Explanation :

The Constitution of India establishes a federal system of government. It contains all the usual features of a federation Viz., two government, Division of powers, written constitution, Supremacy of constitution, Independent judiciary and Bicameralism. Article 1 says that India is a union of states which implies two things: first, Indian federation is not the result of an agreement by the states and second, No state has the right to secede from the federation.