A developer is writing a smart contract for a DeFi lending protocol. The contract allows users to deposit collateral and borrow stablecoins. The developer wants to avoid reentrancy attacks. Which implementation is the most secure?

Use a checks-effects-interactions pattern and a reentrancy guard

Use `transfer` instead of `call` to send ETH

Use `call` with a gas limit of 10000

Use a proxy contract to separate logic and storage

A DAO is implementing a governance system where token holders can delegate their voting power to representatives. The team wants to ensure that the delegation system is secure and resistant to vote buying. Which measure is most effective?

Allow delegation but require the delegator to pay a fee for each delegation.

Allow delegation but limit the total voting power that any single representative can hold.

Allow delegation to any address, but require a minimum delegation period before the vote is counted.

Allow delegation only to addresses that have been verified through a KYC process.

What is the primary role of a liquidity provider (LP) in a DeFi lending protocol?

To govern the protocol's risk parameters

To supply assets to a pool so that others can borrow them

To liquidate undercollateralized positions

To set interest rates for borrowers

In a token-based voting system within a DAO, what does a user's voting power typically depend on?

The number of governance tokens they hold

Their reputation score calculated by the DAO's algorithm

The length of time they have been a member of the DAO

The number of proposals they have submitted in the past

A developer is building a DeFi aggregator that routes trades across multiple DEXs to get the best price. The aggregator uses smart contracts to interact with each DEX. Which principle of DeFi is most critical to the aggregator's success?

Composability, allowing the aggregator to integrate with multiple DEXs and combine their liquidity.

Transparency, ensuring that all trades are visible on the blockchain.

Censorship resistance, ensuring that no entity can block trades.

Permissionless access, allowing anyone to use the aggregator without approval.

EC-CouncilBlockchain Developer Certification

Domain 7Objective 6

DeFi Smart Contracts and Governance BDC Practice Questions (Page 7)

Part of the Blockchain Security and DeFi Development domain, which makes up ~11% of our current practice bank.

42questions here

9free pages

6concepts

Questions 31–35

31expert · hard
A developer is writing a smart contract for a DeFi lending protocol. The contract allows users to deposit collateral and borrow stablecoins. The developer wants to avoid reentrancy attacks. Which implementation is the most secure?
Select an answer first
32application · medium
A DAO is implementing a governance system where token holders can delegate their voting power to representatives. The team wants to ensure that the delegation system is secure and resistant to vote buying. Which measure is most effective?
Select an answer first
33foundation · easy
What is the primary role of a liquidity provider (LP) in a DeFi lending protocol?
Select an answer first
34foundation · easy
In a token-based voting system within a DAO, what does a user's voting power typically depend on?
Select an answer first
35application · easy
A developer is building a DeFi aggregator that routes trades across multiple DEXs to get the best price. The aggregator uses smart contracts to interact with each DEX. Which principle of DeFi is most critical to the aggregator's success?
Select an answer first

Finished these 5 questions?

Review the revealed explanations, or continue through the curriculum.

Next 5 questions →Back to BDC

Free Basic Practice is a study aid with revealable answers — not a scored exam. Examers.io is independent and not affiliated with or endorsed by EC-Council. “BDC” is a trademark of its owner, used for identification only.