(a) Why are many zooflagellates important to human beings ? List any two such zooflagellates which cause disease in human beings. Name the disease as well.
(b) Which zooflagellate inhabits the intestine of termites as a symbiont? What role does this organism play in the termite intestine ?

Explanation

(a) Many zooflagellates are parasites and cause diseases in human beings. (i) Leishmania donovani. It causes kala-azar disease (visceral leishmaniasis).
(ii) Trypanosoma gambiense. It causes sleeping sickness (Trypanosomiasis).
(b) Trichonympha is a cellulose-digesting insect-gut zooflagellate which inhabits the intestine of termites as a symbiont. The termites devours wood but fails to digest it. This protozoans secretes glucosidases which convert cellulose into glucose. The digested food is shared by both the partners. Without Trichonympha, the termits starve and die.