CCE Smart Contracts and Ethereum 3

Question 1

What is a blockchain oracle?

Accepted Answer

A service that provides smart contracts with real-world external data they cannot access directly

Answer

A specialized node that validates and finalizes blocks faster than regular nodes

Answer

A consensus mechanism that uses trusted validators to approve transactions

Answer

A hardware security module for generating cryptographically secure private keys

Question 2

What is a DAO (Decentralized Autonomous Organization)?

Accepted Answer

An organization governed by smart contracts and token holder voting rather than traditional management

Answer

A government agency responsible for regulating cryptocurrency markets

Answer

A type of air-gapped hardware wallet for institutional cryptocurrency storage

Answer

A centralized trading platform that operates without human customer support

Question 3

What does Ethereum's DELEGATECALL opcode do?

Accepted Answer

Executes another contract's code but within the storage context of the calling contract

Answer

Transfers an exact amount of Ether from one contract address to another

Answer

Assigns admin permissions of the calling contract to a designated delegate address

Answer

Batches multiple external contract calls into a single atomic transaction

Question 4

What is the primary purpose of the proxy contract pattern in smart contract development?

Accepted Answer

To enable smart contract logic to be upgraded while preserving the same contract address

Answer

To anonymize transactions by routing them through an intermediary contract

Answer

To reduce gas costs by compressing and batching multiple calls into one transaction

Answer

To clone an existing contract's functionality at a significantly lower deployment cost

Question 5

What is 'front-running' in the context of Ethereum smart contracts?

Accepted Answer

When a miner or bot detects a pending profitable transaction and inserts their own transaction ahead of it with a higher gas fee

Answer

A technique to pre-confirm transactions before they reach the mempool

Answer

The process of pre-mining a new token before its public launch date

Answer

Testing a contract's functions on a testnet before deploying it to mainnet

Question 6

What service does Chainlink primarily provide to the blockchain ecosystem?

Accepted Answer

A decentralized oracle network that securely connects smart contracts to real-world data and APIs

Answer

A layer 2 rollup solution that increases Ethereum's transaction throughput

Answer

A cross-chain bridge protocol for transferring assets between incompatible blockchains

Answer

A decentralized exchange aggregator that routes trades across multiple liquidity pools

Question 7

What does the 'selfdestruct' function do when called in a Solidity smart contract?

Accepted Answer

It removes the contract's bytecode and storage from the blockchain state and sends remaining Ether to a specified address

Answer

It permanently pauses the contract so no functions can be called until it is reactivated

Answer

It encrypts the contract's source code to prevent competitors from reverse engineering it

Answer

It transfers ownership and administrative control of the contract to another specified address