Am sure you would have heard about this question in your interviews. Let's a bit more about it in this post.

In triggers, we have a few context variables like, Trigger.old Trigger.newMap, Trigger.oldMap and etc.

The content of and Trigger.old is going to be List and the content of Trigger.newMap and Trigger.oldMap is going to be a map (as in the same you will be presented the same content but in a different representation).

In fact, we can also use as shown below and it's going to work absolutely fine.

trigger AccountTrigger on Account(before update){

	List[Account] accounts = [Select Id, Name FROM Account WEHRE Id IN:]

} used in SOQL query

Hope this was helpful!