What is the role of nodes in the Bitcoin network?

Nodes play a crucial role in maintaining the integrity and functionality of the Bitcoin network by validating transactions and keeping a copy of the blockchain, which contains all confirmed transactions. This validation process ensures that all transactions comply with the rules of the Bitcoin protocol, preventing double spending and ensuring that only valid transactions are included in the blockchain.

Furthermore, by maintaining a distributed ledger, nodes contribute to the overall security and decentralization of the network. Each node independently verifies transactions and blocks, so even if some nodes fail or go offline, the network remains robust and operational. This decentralized consensus is fundamental to Bitcoin's trust model, allowing users to transact without relying on a central authority.

In contrast to the other options, mining is specifically the task of specialized nodes called miners, which primarily compete to create new blocks, but it is not the sole responsibility of all nodes. Nodes do not create entirely new cryptocurrencies; rather, they operate within the confines of the Bitcoin protocol. Additionally, while nodes can store private keys, this function isn't part of their main operational role; storing private keys is a user-specific task, often handled by wallets rather than the network nodes themselves.