How are the transactions of a cosmos sdk application are validated

when i study cosmos sdk application development, i have a confusion about how its transactions are validated. It looks to me only the application itself know how to validate its transactions, then how validators can do the validation.

Every node (including validator node) runs a copy of the application, so the validation (CheckTx) is done by the application in the validator node.

The blockchain acts as a state replication machine, so all copies of the application should (eventually) get to the same state.

can someone help

Im Not a Developer - need support with lost transaction - ATOM to BNB wallet (Binance to UNICAS) Miscellaneous

Hi, I made a transaction from Binance platform (of my ATOM balance) to a BNB Wallet in a platform named UNICAS (i know, im a dummy - my first time and still figuring things out). Binance claims that they cannot help because the transaction shows successful on their platform. Gave the Transcation Hash ID to Unicas staff so they could reverse. However, Unicas claims that they are not able to locate such a Transaction using the Hash ID i gave them. This is really worrying me… Can someone please …