Is it true that all blockchains are public?

Is it true that all blockchains are public?

Is it true that all blockchains are public?

Not all blockchains are public but many popular ones are.

On a public blockchain, everyone can see all transactions and anyone can participate at all levels. This is not true in private blockchains,

See https://www.itproportal.com/features/breaking-down-blockchain-10-common-misconceptions/