Final answer:
A 'nonce' is the solution to a computational challenge in the Proof-of-Work consensus mechanism, allowing miners to add blocks to the blockchain, such as in Bitcoin. Cryptocurrencies are decentralized digital currencies not issued by a central bank, with values determined by market supply and demand.
Step-by-step explanation:
In the Proof-of-Work (PoW) consensus mechanism, a miner solves an unpredictable math problem to find a specific solution, which in the context of blockchain and cryptocurrency, is referred to as a nonce. This nonce is essentially the answer to a complex mathematical puzzle that validates and, therefore, allows the miner to add a new block to the blockchain. For example, in the Bitcoin blockchain, successfully finding this nonce and adding a block confers on the miner a certain number of bitcoins as a reward, which is also called a block reward.
Cryptocurrency, including Bitcoin, is considered a digital currency that operates independently of a central authority and is not considered fiat currency since it's not issued by a central bank. The decentralized nature of cryptocurrency is maintained through these consensus mechanisms like PoW. The value of a cryptocurrency is largely driven by market forces, mainly supply and demand, although governments can influence this through regulations within their jurisdictions.