Explanation:

The other three are Federal features that show equal division of powers between the Centre and the States. ‘Supremacy of the Constitution’ ensures that the Centre cannot go out of the purview of the Constitution, and hence cannot dominate the States in various spheres. ‘Bicameralism’ i.e. Two houses of Parliament represent both  States and Union where the upper house called Rajya Sabha is a Council of States and thus states have a say at the Union level. ‘Rigidity of the Constitution’ means that the federal provisions of the Constitution cannot be amended without the consent of more than half the States’ legislatures.