Each and every grouping of transactions is became a block and chained to the prevailing ledger. At the time a block is additional it can't be reversed or altered — And that's why individuals explain blockchains as "immutable." 以太币是以太坊的原生货币。要使用以太坊应用，你需要在钱包中预留一些以太币。 There are numerous cryptocurrencies and plenty of other tokens on Ethereum, https://ethbase.net/bitcoin-balks-at-the-summit-ethereum-continues-its-ascent