# Exercises
These questions are meant to refresh your memory on the chapter. 

**Explain the real-world implications of the Byzantine Generals Problem.** 
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**Describe the structure of Blockchain-as-a-data-structure.**
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**How do we calculate the root of a merkle tree?**
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**Two nodes point to the same node. Is this data structure a tree or a linked list?**
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**What is the role of the Genesis Block?**
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**How do we determine whether a piece of data is valid and can be added to the blockchain?**
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**Describe the general structure of a block header.**
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**How does a blockchain add/validate blocks?**
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**What happens when a blockchain network *doesn't* have an honest majority?**
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**In a blockchain system, do we need to trust individual participants? Why or why not?**
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