A Blockchain consists of a list of records(some or all of the recent transaction). Such records are stored in blocks. Each time a block gets completed, a new block is generated. The block linked with other blocks constitutes a chain of blocks called Blockchain. Each block, after added into the blockchain, will be stored as a permanent database. We cannot delete or reverse any block from the blockchain.

In blockchain technology, a block is a fundamental unit of data that contains a list of transactions or information. These blocks are linked together in a chronological and immutable chain through cryptographic hashes, forming the blockchain. Each block typically includes a timestamp, a reference to the previous block (except for the genesis block), a nonce, and a Merkle tree that represents the transactions within the block.

Here’s a breakdown of the key components:

Timestamp: Indicates the time when the block was created, providing a chronological order to the blocks.
Previous Block Hash: A reference to the hash of the preceding block in the chain, creating the link between blocks and ensuring the integrity and continuity of the blockchain.
Nonce: A random number used in the mining process to find a suitable hash for the block. Miners repeatedly change the nonce until they find a hash that meets certain criteria, demonstrating proof of work.
Merkle Tree: A cryptographic tree structure that organizes transactions in the block efficiently, allowing for quick verification of the integrity of a transaction within the block.

By combining these elements, blocks in a blockchain form a secure and transparent ledger of transactions that is resistant to tampering and provides a decentralized and distributed consensus mechanism.