Solution:The preamble to the constitution of India is a brief introductory statement that sets out the guiding purpose, principles and philosophy of the Constitution. Preamble gives idea about the source of the Constitution, nature of Indian State (democratic, sovereign, socialist, secular, republic) a statement of its objectives and the date of its adoption.
The 42nd Amendment Act amended the Preamble and changed the description of India from ‘sovereign democratic republic’ to a ‘sovereign, socialist secular democratic republic’, and also changed the words ‘unity of the nation’ to ‘unity and integrity of the nation’.