Explanation:

Preamble finds the mention of the words “Sovereignty, Unity and Integrity”.

However, if you try to focus on the complete sentence i.e “To uphold and protect the Sovereignty, Unity and Integrity of India” is a provision mentioned in Article 51-A of the Constitution i.e Fundamental Duties.

Fundamental Duties:

• The fundamental duties were incorporated in Part IV-A of our constitution through the 42nd Constitutional Amendment Act, 1976.
• At present, there are eleven fundamental duties under article 51 A of the constitution.
• The idea of Fundamental Duties has been borrowed from the erstwhile USSR.
• Originally the duties were ten in number, later on through 86th Amendment Act, 2002, the eleventh Fundamental duty was added.
• Swaran Singh Committee recommended the inclusion of Fundamental Duties in the Indian Constitution.
• Fundamental duties are non-enforceable in nature.

Following are the eleven Fundamental Duties:

• To abide by the Constitution and respect its ideals and institutions, the National Flag and the National Anthem.
• To cherish and follow the noble ideals which inspired our national struggle for freedom.
• To uphold and protect the sovereignty, unity, and integrity of India.
• To defend the country and render national service when called upon to do so.
• To promote harmony and the spirit of common brotherhood amongst all the people of India transcending religious, linguistic and regional or sectional diversities; to renounce practices derogatory to the dignity of women.
• To value and preserve the rich heritage of our composite culture.
• To protect and improve the natural environment including forests, lakes, rivers, wildlife and to have compassion for living creatures.
• To develop the scientific temper, humanism and the spirit of inquiry and reform.
• To safeguard public property and to abjure violence.
• To strive towards excellence in all spheres of individual and collective activity, so that the nation constantly rises to higher levels of endeavour and achievement.
• To provide opportunities for education to his child or ward between the age of six to fourteen years. This duty was added by the 86th Constitutional Amendment Act, 2002.

Source: Indian Polity by Laxmikanth