The core foundation of Web3 is blockchain, which is a decentralized system that operates on a peer-to-peer network. Depending on their purpose, different blockchains use different working mechanisms. The main function of block-chain is storing data and information with feature like transparency, encryption and immutability. The Bitcoin blockchain is mainly developed using C++, and Bitcoin transactions use a scripting language called Bitcoin Script. Decentralized blockchains are operated and maintained by nodes, such as miners, full nodes, and light nodes, which keep the network running without a central authority. Later, more advanced blockchains were built to support smart contracts, using programming languages like Solidity, Rust, and Move.

You want to imagine what blockchain looks like ?

Think like different computer are connect with each other. each computer is node which keeps the copy of every activity in network. if someone try to change anything in network then every computer will check that activity is legit or not.

We will learn more about blockchain in advance series, for now think it like a decentrilized database. Also i would recommned you to read article on "how internet work" LINK, because to get deeper understanding on blockchain you need to know how internet work.

Crypto currencies are digital currencies backed by smart contract for certain rules and encryption on block-chain. The first crypto currency was bitcoin created in 2009 A.D by anonymous person or organization called satoshi nakamoto. Bitcoin was created on top of bitcoin block chain. Think this like a number on screen but backed by rules.

Fungible means something is interchangeable, where every unit is exactly the same as any other. For example, 1 Bitcoin is equal to another Bitcoin, and a $100 note is the same as any other $100 note. You can swap them without caring which one you get.

Non-fungible, on the other hand, means unique and not interchangeable. Each NFT is different, even if two look identical, because they have their own unique metadata and token ID on the blockchain.

NFTs (Non-Fungible Tokens) are proof of ownership built on the blockchain. Anything in text, picture, video, or token ID deployed on the blockchain can be an NFT. Even if two NFTs look the same, they are not the same on the blockchain. Each has its own metadata and token ID, which makes it distinct from all others. Think of it like two artists creating the same painting: although they look identical, the value of each will be different. There is a clear difference between the original Mona Lisa and a photocopy, even if they appear the same.

There is one more things similar to NFTs called as SBT (soul bounded token) which means a token which cannot be trade or transfer from owner account to other user account which we will learn in advance series. Both NFTs and SBTs are deployed on block-chain and both have their own smart contract rules which make them different from each other.

Smart contracts are self-executing programs which is develop by block-chain language like solidity, rust, move and so on. Point to be noted bitcoin is not build by smart contract but by C++ and run by bitcoin script. Only the modern block-chain like eth, sol, sui are smart contract platform and can run smart contract.

Smart contracts remove the need for intermediaries by automatically executing rules written in code. Once deployed, a smart contract cannot be changed easily, which means developers must be careful while writing them.

Node runner are the backbone of block-chain that are responsible for maintaining, updating and backup the information on block-chain. Node runner include light node runner, full node runner, miners and so on. Node runner earn crypto which is one of the earning scope of web 3.