The host asks for gaia.cs.umass.edu, with every cache empty. As Kurose & Ross point out, in theory any DNS query can be iterative or recursive: choose how each server handles the queries it receives and see what changes.
How each server handles the queries it receives
Examples:
message 0 / 8
QueryReferral (“I don’t know, ask…”)Reply with the addressServer holding someone else’s pending query (it must remember it and wait)