Is immutable on Ethereum?

Is immutability truly a cornerstone of Ethereum?" I ask with a tone of genuine curiosity, folding my arms as I lean forward, seeking clarity. Ethereum, as we all know, prides itself on being a decentralized, open-source blockchain platform. But does it truly embody immutability, that fundamental characteristic that ensures the integrity and security of transactions? Or are there loopholes, exceptions to this rule that could potentially compromise its reliability? I'm eager to understand the intricacies of this concept, how it applies to Ethereum's architecture, and what measures are taken to uphold this supposed immutability. After all, in the fast-paced and constantly evolving world of cryptocurrencies, it's crucial to stay informed and question the assumptions we hold dear.