We pick d.root-servers.net, one of the 13 root servers (1), and ask it about aris2.udsm.ac.tz and learn that tz is delegated to seven name servers (2), so we ask sns-pb.isc.org where we learn that udsm.ac.tz is delegated to two name servers, including dns.ucc.co.tz (3), so we ask that one and get the following answer: