Ethereum Architecture and Transaction Lifecycle BBLC Practice Questions (Page 2)

Questions 6–10

1. 6foundation · easy

   In an Ethereum transaction, what is the purpose of the nonce field?

   • ATo count the number of transactions sent from a given account and prevent replay attacks
   • BTo identify the recipient of the transaction
   • CTo store the digital signature of the sender
   • DTo specify the maximum amount of gas the transaction can consume
   Reveal Solution Discussion Select an answer first
2. 7application · medium

   A developer is deciding where to run an Ethereum node for a production dApp. They need to reliably query contract state and event logs. Which node deployment is most appropriate?

   • AA full node that stores the entire blockchain and executes all transactions.
   • BAn archive node that stores all historical states, which is unnecessary for this use case.
   • CA light node that only stores block headers and requests state from peers.
   • DA mining node that participates in consensus and validates transactions.
   Reveal Solution Discussion Select an answer first
4. 8application · medium

   A smart contract A calls a function in smart contract B. From the perspective of the Ethereum protocol, what is this interaction called?

   • AAn event, because it emits a log.
   • BA transaction, because it changes the state of contract B.
   • CA contract creation, because contract B is being created.
   • DA message call, initiated by contract A and executed in the context of contract B.
   Reveal Solution Discussion Select an answer first
5. 9foundation · easy

   What is a key role of a contract account (smart contract) on Ethereum?

   • ATo execute predefined logic when it receives a transaction or message
   • BTo sign transactions on behalf of its owner
   • CTo store the private keys of its users
   • DTo act as a network node that validates blocks
   Reveal Solution Discussion Select an answer first
6. 10expert · hard

   A user submits a transaction with a low gas price during a period of network congestion. The transaction remains in the mempool for hours. What is the most likely outcome, and what should the user do?

   • AThe transaction will be included in the next block because the protocol guarantees inclusion.
   • BThe transaction may never be included; the user should resubmit with a higher gas price or use a transaction replacement.
   • CThe transaction will eventually be included because all transactions are processed in order.
   • DThe transaction will be automatically canceled after 10 minutes.
   Reveal Solution Discussion Select an answer first