This concludes our Introduction to Bitcoins. We have covered a lot in this module. To recap, every bitcoin transaction consists of inputs and outputs. The outputs are almost always UTXOs, that get referenced as inputs in subsequent transactions.
Miners validate these transactions, but, most of the time they spend goes into showing the Proof-of-Work. Because of the distributed nature of Bitcoins, each miner receives a different set of transactions and so just having the most powerful computer isn't sufficient to be able to commit fraud on the network.