Ethereum's Purpose, Ecosystem, and Evolution BDC Practice Questions (Page 5)

Questions 21–25

1. 21expert · hard

   A developer is explaining to a client why Ethereum's transition to proof-of-stake did not automatically make all DApps faster. The client assumes that the Merge would reduce transaction latency. Which statement accurately addresses this misconception?

   • AThe Merge changed the consensus mechanism but did not increase throughput or reduce latency; those are addressed by later upgrades like sharding.
   • BThe Merge increased block gas limits, allowing more transactions per block and thus faster processing.
   • CThe Merge reduced the block time from 15 seconds to 5 seconds, making transactions confirm faster.
   • DThe Merge eliminated gas fees, so transactions are processed immediately without waiting.
   Reveal Solution Discussion Select an answer first
2. 22expert · hard

   A company has been running a proof-of-work Ethereum node since 2017. After the Merge, they notice their node's energy consumption has dropped significantly, but they are concerned about the security implications of the new consensus mechanism. Which statement accurately addresses their concern?

   • AProof-of-stake relies on validators staking Ether, and an attacker would need to control a large portion of staked Ether to compromise the network.
   • BProof-of-stake is less secure than proof-of-work because it uses less energy.
   • CProof-of-stake is centralized because only large holders can validate.
   • DProof-of-stake requires specialized hardware to validate.
   Reveal Solution Discussion Select an answer first
4. 23expert · hard

   A developer is evaluating whether to build a new DApp on Ethereum mainnet or on a sidechain. The DApp requires high throughput and low fees, but also needs to inherit the security of Ethereum mainnet. Which option best balances these requirements?

   • AUse a standalone sidechain with its own consensus mechanism.
   • BUse a centralized database with a blockchain-like API.
   • CUse Ethereum mainnet directly and accept the high fees.
   • DUse a Layer 2 rollup that posts transaction data to Ethereum mainnet.
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5. 24application · medium

   A startup wants to build a decentralized application where users can trade tokenized carbon credits directly with each other, without a central authority managing the trades. They need a platform that supports custom business logic and transparent, auditable transactions. Which approach best fulfills this requirement?

   • AUse a cloud-based file storage service to store trade records and rely on client-side code to enforce trading rules.
   • BCreate a private blockchain using a generic distributed ledger framework and host it on a single server.
   • CUse a traditional relational database with a REST API to manage trades and issue tokens as database entries.
   • DDeploy a smart contract on Ethereum that defines the token and the trading rules, and provide a web interface that interacts with the contract.
   Reveal Solution Discussion Select an answer first
6. 25foundation · easy

   Which statement best describes the role of smart contracts within the Ethereum ecosystem?

   • ASmart contracts are temporary scripts that run only during a transaction and are deleted immediately after execution.
   • BSmart contracts are legal documents that are stored on the blockchain but require manual execution by contract lawyers.
   • CSmart contracts are off-chain scripts that require a trusted third party to execute and validate each transaction.
   • DSmart contracts are programs stored on the blockchain that automatically execute predefined actions when certain conditions are met.
   Reveal Solution Discussion Select an answer first