Ethereum's Purpose, Ecosystem, and Evolution BDC Practice Questions (Page 8)

Questions 36–40

1. 36expert · hard

   A developer is evaluating whether to build a DApp on Ethereum mainnet or on a Layer 2 solution. The DApp requires low transaction costs and high throughput, but also needs to inherit Ethereum's security. Which consideration is most important in this decision?

   • ALayer 2 solutions offer lower fees and higher throughput while relying on Ethereum for security, but they may introduce trust assumptions in their bridging mechanisms.
   • BEthereum mainnet has no transaction fees, making it the best choice for cost-sensitive DApps.
   • CEthereum mainnet provides higher throughput than any Layer 2 solution.
   • DLayer 2 solutions are not compatible with Ethereum smart contracts, so the DApp would need to be rewritten.
   Reveal Solution Discussion Select an answer first
2. 37application · medium

   A developer is writing a deployment guide for a new DApp and wants to note the historical milestone that introduced the Ethereum Virtual Machine (EVM) as the execution environment for smart contracts. Which milestone should they reference?

   • AHomestead
   • BMetropolis
   • CSerenity
   • DFrontier
   Reveal Solution Discussion Select an answer first
4. 38application · medium

   A developer is writing a script that needs to interact with the Ethereum blockchain to read the balance of a user's wallet and send a transaction. Which combination of Ethereum ecosystem components is required?

   • AA wallet (e.g., MetaMask) and a compiler (e.g., Solc)
   • BA testnet and a faucet
   • CA node (e.g., Geth) and a library (e.g., Web3.js)
   • DA miner and a block explorer
   Reveal Solution Discussion Select an answer first
5. 39expert · hard

   A developer is planning to deploy a smart contract that relies on the block number to determine when a certain action can be executed. After the Merge, they are concerned about whether the block number behavior has changed. What should they consider?

   • ABlock numbers are no longer available after the Merge.
   • BBlock numbers now reset to zero after the Merge.
   • CBlock numbers continue to increment at a similar rate, but the consensus mechanism change may affect block time variability.
   • DBlock numbers are now determined by validators instead of miners.
   Reveal Solution Discussion Select an answer first
6. 40expert · hard

   A startup is building a decentralized identity system where users control their own data. They want to store identity attributes on-chain but are concerned about privacy. Which approach best balances transparency and privacy?

   • AAvoid using Ethereum and use a centralized identity provider
   • BStore all identity data directly in the smart contract
   • CUse a private blockchain with no public access
   • DStore only hashes or references to off-chain data on-chain, using smart contracts to manage access control
   Reveal Solution Discussion Select an answer first