Is every bitcoin transaction (eventualy) validated by every miner? I can see that my bitcoin transfers becomes real when my exchange detects 2 or more confirmations.

I believe each confirmation is a validation. Am I correct? If so, How many confirmations will have my transaction? As many as miners does exist? If not, how many?
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Each node validates all transactions in every block and, every block in its entirety.

The confirmation count is how many blocks are mined on top of the block that includes your transaction. A new block is mined every ten minutes on average.