Which of the following institutes said in its judgement that no part of our Constitution is unamendable?

In the landmark Kesavananda Bharati v. State of Kerala (1973) case, the Supreme Court ruled that while Parliament has wide amending power, no part of the Constitution is completely unamendable. However, Parliament cannot alter the 'basic structure' of the Constitution. This was a balanced approach between Parliament's amending authority and judicial review. High Courts follow Supreme Court precedent on constitutional matters.