An amendment of this Constitution may be initiated only by the introduction of a Bill for the purpose in either House of Parliament, and when the Bill is passed in each House by a majority of the total membership of that House present and voting, it shall be presented to the President who shall give his assent to the Bill and thereupon the Constitution shall stand amended in accordance with the terms of the Bill: Provided that if such amendment seeks to make any change in.

The correct answer is option 'A': sovereignty, territorial integrity, Federal System, and judicial review.

Sovereignty:
- Sovereignty refers to the supreme power or authority of a state to govern itself without any external interference.
- The Indian Constitution declares India as a sovereign, socialist, secular, and democratic republic.
- The concept of sovereignty is enshrined in the Preamble of the Constitution and is a basic feature that cannot be amended.

Territorial Integrity:
- Territorial integrity refers to the inviolability of a country's borders and the unity of its territory.
- The Indian Constitution ensures the territorial integrity of the country by defining its boundaries and providing for the protection and preservation of its territory.
- Any attempt to alter the territorial integrity of India would require a constitutional amendment and cannot be done under Article 368.

Federal System:
- The Indian Constitution establishes a federal system of government where power is divided between the central government and the state governments.
- This division of power is enshrined in the Seventh Schedule of the Constitution, which lists the distribution of powers between the Union and the states.
- The federal structure of India is a basic feature of the Constitution and cannot be amended under Article 368.

Judicial Review:
- Judicial review refers to the power of the judiciary to review and strike down laws and actions that are unconstitutional.
- The Indian Constitution grants the power of judicial review to the Supreme Court and the High Courts.
- This power is essential to ensure the supremacy of the Constitution and protect the fundamental rights of individuals.
- Judicial review is considered a basic feature of the Constitution and cannot be amended under Article 368.

Parliamentary System of Government:
- While not mentioned in the options, it is important to note that the Indian Constitution also establishes a parliamentary system of government.
- This system is based on the principle of the separation of powers, with the President as the head of state and the Prime Minister as the head of government.
- The Parliament consists of two houses - the Lok Sabha (House of the People) and the Rajya Sabha (Council of States).
- The parliamentary system of government is a basic feature of the Constitution and cannot be amended under Article 368.

In conclusion, the basic features of the Indian Constitution that are not amendable under Article 368 are sovereignty, territorial integrity, Federal System, judicial review, and the parliamentary system of government. These features are considered fundamental to the Constitution and provide the framework for governance in India.