# Exercises
These questions are created to help you refresh your information on this
chapter.

**What is the composition of a Bitcoin block header? Explain why the
different fields are there.**
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**What is the data of the Bitcoin blockchain? What is its composition?**
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**Briefly explain the UTxO model**
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**What is Script?**
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**How does a full node verify that a UTxO is unspent?**
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**How is the miner rewarded for creating a new block in Bitcoin?**
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**Describe the difference between a Custodial and Non-Custodial wallet?**
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**How does Bitcoin create new Bitcoin tokens?**
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**Bill just lost his JBOK wallet. Bill says its no big deal and that
he can recreate it. Is Bill correct? If not what type of wallet is recoverable?**
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**Briefly describe how a Bitcoin transaction is created, broadcast and confirmed.**
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