*A foundational level of blockchain architecture, operating as the primary and autonomous chain on which transactions are directly executed and confirmed

*A network built on top of Ethereum that enhances scalability by processing transactions off-chain before settling on the mainnet

*A decentralized Layer 1 network that supports smart contracts, security, and a thriving ecosystem of decentralized applications (dApps)

*An application-focused and driven network

*Ethereum should serve as a secure settlement layer while rollups and Layer 2 solutions handle execution and customization

*The App-Chain Thesis

*All of the above

*Scalability

*Rollups

*No, Other types of Layer2 networks include State Channels, Plasma and Validiums

*A Layer2 network built on Ethereum that bundles multiple transactions into a single batch for efficiency

*By processing transactions off-chain and settling them on Ethereum, reducing execution costs and load on Layer 1

*They process transactions off-chain, reducing congestion and lowering costs on the main blockchain

*Optimistic and Zero-Knowledge (ZK) rollups

*They assume all transactions are valid by default and allow for fraud proofs to challenge invalid transactions

*By using zero-knowledge proofs to validate transactions off-chain and submitting a succinct proof to the main chain

*Lack of inter-L2 connectivity

*Fragmented and insecure interoperability solutions