Ethereum and Smart Contracts

Which statements about Ethereum are correct? (2 correct answers). Ethereum was created by Vitalik Buterin. Ethereum can only transfer cryptocurrency. Ethereum supports smart contracts. Ethereum uses SHA-256 as its main hash. Ethereum cannot run programs.

Which are properties of Keccak-256 in Ethereum? (2 correct answers). It is used for all hashing in Ethereum. It is reversible. It is similar to SHA-3. It is only used for wallets. It allows collisions.

What are advantages of blockchain? (2 correct answers). Transparency. High performance. Immutability. Centralized control. Unlimited scalability.

Which are types of Ethereum accounts? (2 correct answers). Mining accounts. External Owned Accounts. Contract Accounts. Validator Accounts. System Accounts.

Which fields belong to an Ethereum account? (3 correct answers). Nonce. Balance. CodeHash. IP address. MAC address.

Which statements about transactions are correct? (2 correct answers). They can deploy contracts. They are unsigned. They modify blockchain state. They cannot execute code. They are anonymous and unverifiable.

Which are Ether denominations? (3 correct answers). Wei. Finney. Szabo. Dollar. Satoshi.

Which are characteristics of smart contracts? (3 correct answers). They are executable programs. They can hold funds. They are Turing complete. They run outside the blockchain. They cannot interact with users.

Which statements about the EVM are correct? (2 correct answers). It executes bytecode. It only runs on one node. Every node contains an EVM. It stores private keys. It replaces the blockchain.

What problems does Gas solve? (2 correct answers). Infinite loops. Energy waste. Uncontrolled execution. Address collisions. Network anonymity.

Which define the cost of a transaction? (2 correct answers). Gas Limit. Gas Price. Block time. Account balance. Hash size.

Which statements about PoS are correct? (3 correct answers). Validators stake ETH. It consumes more energy than PoW. Validators can lose their stake. Block time is fixed. It requires mining hardware.

Which are disadvantages of PoS? (1 correct answer). High energy usage. Risk of centralization. Slow block confirmation. Infinite loops. Lack of cryptography.

Which are parts of an Ethereum block? (3 correct answers). Transaction list. Block header. Ommer list. Wallet list. Balance tree.

Which describe light clients? (2 correct answers). Store full blockchain. Store only headers. Used for balance checking. Validate all blocks. Mine ETH.

Which are properties of Keccak hashes? (2 correct answers). One-way. Reversible. Deterministic. Human-readable. Editable.

Which statements about addresses are correct? (2 correct answers). Derived from the public key. Are random numbers. 40 hex characters + 0x. Stored in plain text. Based on SHA-256.

Which are advantages of PoS? (2 correct answers). Lower energy consumption. More mining. Faster confirmations. More hardware. Less security.

Which are consensus mechanisms? (3 correct answers). PoW. PBFT. DPoS. HTTP. DNS.

Which data is in the block header? (2 correct answers). StateRoot. ReceiptRoot. Private keys. Passwords. IP addresses.

Which describe Merkle-Patricia tries? (2 correct answers). Cryptographically secure. Allow tampering. Root changes if data changes. Store videos. Are centralized.

Which statements about wallets are correct? (2 correct answers). Contain multiple EOAs. Are smart contracts. Store ETH. Replace nodes. Execute code.

Which are smart contract languages? (3 correct answers). Solidity. Serpent. LLL. Java. PHP.

Which are development tools? (2 correct answers). MetaMask. TestRPC. Photoshop. Excel. Word.

Which are steps in the workflow? (3 correct steps). NOT_PART_OF_THE_WORKFLOW: Reset_blockchain Deploy_contract Mine_Bitcoin Fund_account Create_account.

Which statements about TestRPC are correct? (2 correct answers). Local blockchain. Slow transactions. Instant execution. Public network. Requires miners.

Which are features of smart contracts? (2 correct answers). Immutable. Editable anytime. Autonomous. Require admin. Centralized.

Which data does StateRoot store? (3 correct answers). Nonce. Balance. CodeHash. Password. GPS.

Which describe ommer blocks? (2 correct answers). Valid but not main chain. Invalid blocks. Referenced in headers. Store wallets. Only in Bitcoin.

Which describe Ethereum transactions? (2 correct answers). Signed by sender. Change global state. Are anonymous. Contain no data. Cannot fail.