What is a transaction block?

Transaction block is a set of transactions, data in the blockchain network, which is created at a different time for each blockchain. Transactions are confirmed in the block. In the Bitcoin network, a new block containing transactions is opened approximately every 10 minutes on average in the blockchain by extraction.

A block consists of a header and data (transactions). The header contains a reference to the previous block in the chain (its hash), a timestamp for creating the block and the merkle tree root of the transactions in the block. In the data block we have a hash tree of transactions concluded in the block and then the transactions themselves. This way of writing allows you to search for the transaction by its hash, without having to read all data.

What is the average time of cryptocurrencies block extraction?

Bitcoin (BTC) - 10 minutes, 
Bitcoin Cash (BCH)- 10 minutes, 
Litecoin (LTC) - 2.5 minutes,
Ethereum (ETH) - 12-14 seconds,
Ripple (XRP) - 4 seconds.

A block is a record in a blockchain that contains and confirms many pending transactions. A new block containing transactions is opened approximately every 10 minutes in the blockchain by mining.

Transaction blocks are saving data in the network. This data is called a distributed ledger and is inserted into the chain at intervals. In each block there is a timestamp with the date, time and transaction size and signed electronically encrypted with a hash. When the block is in the right size or has reached his time the next one appears with the hash of the previous block. In the bitcoin network block appears on average every 10 minutes. After the transaction is entered into the blockchain, it is no longer reversible, unchangeable and can not be deleted. The first block in the newly created blockchain network is called “genesis block”