# Blockchain 101 #2 / Answers

By [zzmasoud](https://paragraph.com/@zzmasoud-2) · 2022-04-10

---

Hey guys, here are the answers of [Blockchain 101 #2](https://galaxy.eco/zzmasoud/campaign/GCrXuUUgsY) quiz:

![related to the first question](https://storage.googleapis.com/papyrus_images/fe2b45ebf95e89594d6838d35965cface65e4ffbf55c246be3ac5b9f7372fabb.png)

related to the first question

Q: Name the common type of ledgers that can be considered by users in Blockchain? A: Decentralized network / (B) Centralized network / (C) Distributed network

Q: What is the task of miners in a blockchain network? A: Miners are nodes that compete for a reward by calculating the correct nonce to make a transaction possible.

Q: What does a nonce do? A: Adds randomness to the hash

Q: How many characters does the SHA256 hash produce? A: 64

Q: How is blockchain achieve immutability? A: passing the hash of the current block to the next block

Q: \_\_\_\_\_\_ are the part that keeps a copy of the blockchain, verifies transaction signatures, and throws out invalid transactions. A: nodes

Q: which phrases are TRUE about Merkle Tree? (multiple choice) A: is a data structure. / non leaf nodes don’t contain transaction IDs. /leaf nodes are the transaction IDs.

Q: What are the properties of a Hash Function ? (multiple choice) A: Fixed Length / One-way function

Q: Bob wants to verify Alice's signature. So he has to use \_\_\_\_\_\_. A: Alice's public key

Q: The "nonce" is \_\_\_\_\_\_\_. A: The number that miners solve

---

*Originally published on [zzmasoud](https://paragraph.com/@zzmasoud-2/blockchain-101-2-answers)*