The parasite trypanosoma cruzi, which causes chagas disease, has a crystalline rod inside of its flagellum and a kinetoplast; in what protozoan group does it belong?

The answer is kinetoplastida group/class.

The kinetoplastida class is formed by a group of flagellated protists and something caracteristic about this group is the the presence of an organelle with DNA called kinetoplast. This group includes some parasites like trypanosoma cruzi, who are responsible for serious diseases in animals and humans.