Full node is an implementation of a blockchain protocol. It maintains a complete copy of the entire blockchain ledger and participates in validating transactions and blocks as part of the consensus process. A full node also stores all transaction data, smart contracts and other information related to the network’s operations. Full nodes are actively involved in the verification process, helping to ensure that the network remains secure and reliable for users.

As the most important part of any decentralized network, full nodes play an essential role in maintaining trust and security within a blockchain ecosystem. With full nodes, users can trust that the network is operating accurately and securely. They also help to ensure faster transaction speeds and better scalability for blockchain networks. Without full nodes, a network would be prone to various attack vectors and other malicious activity. Thus, full nodes are essential for keeping blockchain networks safe, secure and functioning properly. Ultimately, full nodes are important components of a blockchain system that provide users with trust and security in the network. They are essential for the integrity and health of any blockchain-based solution.

A blockchain full node is like a library where all the books are kept. Each book is like a block of information and the library has all the books in a series in order. The books in the library are like the information on the blockchain, and the library is like the full node. Just like how a library allows people to come and read books, a full node allows people to see and access all the information on the blockchain..

Bitcoin Full Node: This is the most popular full node in blockchain, and it is responsible for verifying transactions on the Bitcoin network. It stores a complete copy of the Bitcoin ledger, meaning that it can independently validate transactions, ensuring that no double-spending takes place. 

Ethereum Full Node: An Ethereum full node runs the Ethereum Virtual Machine (EVM), which allows developers to deploy decentralized applications onto the Ethereum network. By running an Ethereum full node, users can ensure that their local copy of the blockchain is up-to-date and secure. 

Ripple Validator Node: Ripple validator nodes are used to validate transactions on the Ripple network. Unlike other blockchains, Ripple does not rely on miners to process transactions but rather uses a consensus protocol to validate transactions. Ripple validator nodes are essential for keeping the network secure and running smoothly.