We pick b.root-servers.net, one of the 13 root servers (1), and ask it about lagranja.gov.ar and learn that ar is delegated to five name servers (2), so we ask ns2.switch.ch where we learn that lagranja.gov.ar is delegated to two name servers, including thor.secyt.gov.ar (3), so we ask that one where we see a CNAME from lagranja.gov.ar to civitas.gob.ar, so we have to start all over again. We already know that ar.cctld.authdns.ripe.net is authoritative for ar (4) and ask it about civitas.gob.ar and learn that civitas.gob.ar is delegated to two name servers (5), so we ask thor.secyt.gov.ar and see a second CNAME from civitas.gob.ar to civitas.gov.ar. We start over for the third time and we already know that ar.cctld.authdns.ripe.net is authoritative for ar (6) and ask it about civitas.gov.ar and learn that civitas.gov.ar is delegated to two name servers (7), so we ask www.civitas.gov.ar and get the following answer:
The two name servers www.civitas.gob.ar and thor.secyt.gov.ar together
There are 15 domains that use name server group 1.
All of those are under the tld "ar".
All of them use the primary name server www.civitas.gob.ar. Worth noting is that all of the domains that use the primary name server www.civitas.gob.ar use name server group 1.
All of them use only the IPv4 number 190.136.32.36. Worth noting is that half of the domains that only use the IPv4 number 190.136.32.36 use name server group 1.
The two name servers proteus and thor.secyt.gov.ar together
There are more than hundred domains that use the two name servers proteus and thor.secyt.gov.ar together, hereafter referred to as "name server group 2".