Question about how name servers work?

[mlmleads]

If I set name servers 1 and 2 to one service and servers 3 and 4 to another service will the internet requests be divided amongst all 4 servers or is it a linear system where it tries dns 1 then 2 and so on until it gets one that is responding?

 

[Constantin]

You can't control it, it is a great chance for the requester to take a random nameserver.