1. How does the Bitcoin network guard against hackers seizing control of the system?
By rewarding for honest work on the network. Bitcoin security is backed by proof of work meaning you need to use computational energy to confirm transactions on the blockchain, for someone to attack the network they would need energy to, so instead of using it maliciously with the risk of getting the transaction rejected by the nodes and your mining pool getting abandoned by most miners (cause only a pool can practically have enough hashrate to attempt a 51% attack).
It is much more rewarding to contribute that to the network and help secure it more.
2. How do miners fit into the Bitcoin network?
Miners are nodes that not only validate transaction but also compete to confirm transactions.
Mining helps to keep the blockchain going and bring new bitcoins into circulation.
3. How is fraud prevented on the Bitcoin network by transaction verification?
Nodes validate every transaction made before propagating it. They confirm that the transaction checks out and that the signing private key is actually in ownership of the bitcoins being sent out.
4. What distinguishes a private key from a bitcoin address?
Private key is used to sign transactions, it is like the proof of ownership of an address.
An address functions as an account number which you would use to receive bitcoins. You addresses are generated from your private keys, but you cannot work the other way, i.e, address to private key.
- Jay -