A preamble is an introductory statement in a document that explains the document’s philosophy and objectives. In a Constitution, it presents the intention of its framers, the history behind its creation, and the core values and principles of the nation.
The Preamble is based on the Objective Resolution moved by Jawaharlal Nehru in the Constituent Assembly on December 13, 1946. The Resolution was adopted on January 22, 1947. Although not enforceable in court, the Preamble states the objects of the Constitution, and acts as an aid during the interpretation of Articles when language is found ambiguous.
The original Preamble, adopted by the Constituent Assembly in 1949, declared India a “Sovereign Democratic Republic”. By the 42nd Amendment of 1976, enacted during the Emergency, the words “Socialist” and “Secular” were inserted; the Preamble now reads “Sovereign Socialist Secular Democratic Republic”.
The 42nd Amendment to the Constitution, passed in 1976, replaced the words “sovereign democratic republic” to “sovereign socialist secular democratic republic”. It also changed “unity of the nation” to “unity and integrity of the nation”.

Under Article 168, states can have either one or two Houses of legislature. Article 169 leaves the choice of having a Vidhan Parishad to individual states. Under Article 171, a Council cannot have more than a third of the number of MLAs in the state, and not less than 40 members. A third of the MLCs are elected by MLAs, another third by a special electorate comprising sitting members of local government bodies such as municipalities and district boards, 1/12th by an electorate of teachers, and another 1/12th by registered graduates. The remaining members are appointed by the Governor for distinguished services in various fields.
Besides Andhra Pradesh, five other states have Vidhan Parishads — Bihar (58 members), Karnataka (75), Maharashtra (78), Telangana (40), UP (100). Jammu and Kashmir had a Council until the state was bifurcated into the Union Territories of J&K and Ladakh.

Fundamental Rights are not absolute and subject to reasonable restrictions. Further, they are not sacrosanct and can be curtailed or repealed by the Parliament through a constitutional amendment act. They promote the idea of political democracy. DPSP promote the idea of social and economic democracy.
Most of them are directly enforceable (self-executory) while a few of them can be enforced on the basis of a law made for giving effect to them. Such a law can be made only by the Parliament and not by state legislatures so that uniformity throughout the country is maintained (Article 35).

42nd Amendment to the Constitution Added three new Directive Principles viz., equal justice and free-legal aid, participation of workers in the management of industries and protection of environment, forests and wild life.

A number of provisions in the Constitution can be amended by a simple majority of the two Houses of Parliament outside the scope of Article 368. These provisions include:
1. Admission or establishment of new states.
2. Formation of new states and alteration of areas, boundaries or names of existing states.
3. Abolition or creation of legislative councils in states.
4. Second Schedule—emoluments, allowances, privileges and so on of the president, the governors, the Speakers, judges, etc.
5. Quorum in Parliament.
6. Salaries and allowances of the members of Parliament.
7. Rules of procedure in Parliament.
8. Privileges of the Parliament, its members and its committees.
9. Use of English language in Parliament.
10. Number of puisne judges in the Supreme Court.
11. Conferment of more jurisdiction on the Supreme Court.
12. Use of official language.
13. Citizenship—acquisition and termination.
14. Elections to Parliament and state legislatures.
15. Delimitation of constituencies.
16. Union territories.
17. Fifth Schedule—administration of scheduled areas and scheduled tribes.
18. Sixth Schedule—administration of tribal areas