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  • Difficulty - Medium
    Total Plays - 18
    Allowed Time - 10 sec
    Best time - 2.746

    Why do upgradeable contracts avoid constructors?

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    Explanation:
    Constructors run only during deployment and do not execute through proxies. Using an initializer ensures state is properly set through proxy calls. The entire proxy pattern relies on replacing constructors with explicit initialization.
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  • Difficulty - Medium
    Total Plays - 19
    Allowed Time - 10 sec
    Best time - 1.746

    Why is assert() dangerous in production?

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    Explanation:
    assert() triggers a Panic error and is intended only for internal guarantees. If it fires in production, it indicates a compiler or logic bug. Developers should use require() for user-facing validation.
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  • Difficulty - Medium
    Total Plays - 18
    Allowed Time - 10 sec
    Best time - 1.487

    Why is msg.value validation kept at the top of functions?

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    Explanation:
    Validating msg.value early ensures no state mutation occurs before detecting invalid ether transfers. This prevents partially updated storage on failure, preserving atomicity. It aligns with checks-effects-interactions
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  • Difficulty - Medium
    Total Plays - 24
    Allowed Time - 10 sec
    Best time - 1.968

    What is a rollup?

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    Explanation:
    Rollups are Layer 2 blockchain scaling solutions that bundle multiple transactions off-chain and then post cryptographic proofs to the main chain. This reduces gas fees and increases transaction speed while maintaining the security and decentralization of the base blockchain. Rollups are key to Ethereum scalability and the future of high-performance Web3 applications.
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  • Difficulty - Medium
    Total Plays - 25
    Allowed Time - 10 sec
    Best time - 1.330

    What does MEV stand for in Ethereum?

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    Explanation:
    MEV (Maximum Extractable Value) refers to profits gained by reordering or inserting transactions in a block. It’s a major focus in blockchain security and DeFi optimization, influencing how validators and searchers interact with the mempool.
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  • Difficulty - Medium
    Total Plays - 29
    Allowed Time - 10 sec
    Best time - 0.936

    What is sharding in blockchains?

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    Explanation:
    Sharding is a blockchain scalability technique that divides the entire network’s data into smaller, manageable pieces called shards. Each shard processes its own transactions and smart contracts, improving network speed, performance, and efficiency. This concept is key for scalable blockchain infrastructure like Ethereum 2.0 and future Web3 ecosystems.
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  • Difficulty - Medium
    Total Plays - 30
    Allowed Time - 10 sec
    Best time - 1.796

    What is a blockchain QA analyst’s task?

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    Explanation:
    A Blockchain QA Analyst is responsible for testing smart contracts, dApps, and blockchain networks to ensure they work as intended. They identify bugs, check performance, and validate security, which is critical for building trust in decentralized applications. This role is increasingly important in blockchain careers, as companies rely on QA analysts to deliver reliable and secure Web3 products.
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  • Difficulty - Medium
    Total Plays - 35
    Allowed Time - 10 sec
    Best time - 0.734

    Which consensus offers fastest finality?

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    Explanation:
    BFT-based (Byzantine Fault Tolerant) consensus mechanisms achieve instant or near-instant finality by requiring agreement among validators in just one round of communication, allowing transactions to be finalized in seconds—faster than PoW, PoS, or DPoS.
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  • Difficulty - Medium
    Total Plays - 32
    Allowed Time - 10 sec
    Best time - 3.504

    What does the immutable keyword do in Solidity?

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    Explanation:
    immutable variables are assigned once during deployment and can’t be changed afterward. They are more gas-efficient than regular storage variables.
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  • Difficulty - Medium
    Total Plays - 32
    Allowed Time - 10 sec
    Best time - 0.985

    Which blockchain introduced smart contracts?

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    Explanation:
    Ethereum popularized smart contracts and allowed developers to build decentralized apps.
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  • Difficulty - Medium
    Total Plays - 34
    Allowed Time - 10 sec
    Best time - 1.883

    Royalties in NFTs allow:

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    Explanation:
    Royalties in NFTs ensure that artists receive a percentage of sales every time their work is resold on secondary markets. This feature provides creators with ongoing income and supports long-term value for their digital art.
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  • Difficulty - Medium
    Total Plays - 28
    Allowed Time - 10 sec
    Best time - 1.238

    Combines PoW and PoS?

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    Explanation:
    Hybrid mechanisms (e.g., Decred) blend PoW mining with PoS voting for balanced security.
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  • Difficulty - Medium
    Total Plays - 23
    Allowed Time - 10 sec
    Best time - 1.725

    "Decentralized oracles" use:

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    Explanation:
    Decentralized oracles (e.g., Chainlink) source data from many nodes for trust.
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  • Difficulty - Medium
    Total Plays - 22
    Allowed Time - 10 sec
    Best time - 1.118

    What is Hash?

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    Explanation:
    A hash function is a algorithm that converts data into a fixed-size string (hash value), used for data integrity, security, or quick lookup.
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  • Difficulty - Medium
    Total Plays - 23
    Allowed Time - 10 sec
    Best time - 0.899

    NFT "minting" means:

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    Explanation:
    Minting converts digital files (art, music) into blockchain-based NFTs.
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  • Difficulty - Medium
    Total Plays - 27
    Allowed Time - 10 sec
    Best time - 0.590

    The first block is called:

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    Explanation:
    The genesis block is the first block in a blockchain, initiating the chain.
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