Deploy and Manage dApps BDC Practice Questions (Page 6)

Questions 26–30

1. 26foundation · easy

   In a dApp, what is the primary purpose of the application binary interface (ABI)?

   • ATo enable the frontend to encode and decode calls to the smart contract
   • BTo define the structure of the frontend user interface
   • CTo store the private keys of the contract owner
   • DTo specify the network protocol for peer-to-peer communication
   Reveal Solution Discussion Select an answer first
2. 27foundation · easy

   What is the recommended practice for managing the private key of a smart contract deployer account?

   • AShare it with all team members for transparency
   • BEncrypt it with a simple password and store it in a public cloud bucket
   • CStore it in a hardware wallet or secure key management service
   • DInclude it in the project's source code repository
   Reveal Solution Discussion Select an answer first
4. 28foundation · easy

   What is a common administrative control in a smart contract to manage parameters like fees or limits?

   • AA public variable that anyone can modify
   • BA hardcoded value that cannot be changed
   • CA function that automatically adjusts parameters based on market conditions
   • DA setter function guarded by an access control modifier
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5. 29application · medium

   A dApp's governance contract allows token holders to vote on parameter changes. The team wants to ensure that only verified token holders can vote and that each token holder can vote only once per proposal. Which mechanism should be implemented?

   • AUse a centralized server to track votes and verify balances via an API.
   • BLet users vote multiple times and count the last vote.
   • CUse a snapshot of token balances at a specific block height and record votes in a mapping.
   • DAllow any address to vote but require a small fee.
   Reveal Solution Discussion Select an answer first
6. 30application · medium

   A developer deployed a Solidity contract to a private Ethereum network using Hardhat. The deployment transaction succeeded, but the contract's constructor state variable was not set. The developer confirmed the constructor code is correct and the deployment script has no errors. What is the most likely cause of this issue?

   • AThe constructor arguments were not passed in the deployment script, so the constructor used default values.
   • BThe contract was deployed to a different network than the one the frontend is configured to use.
   • CThe gas limit was too low, causing the constructor to fail silently.
   • DThe contract was compiled with an older version of the Solidity compiler that ignores constructor arguments.
   Reveal Solution Discussion Select an answer first