You have been studying the relationship between jackals and tigers in India. Until recently, the only relationship you have observed is that jackals will associate themselves with a particular tiger and follow it at a safe distance in order to feed on the big cat's kills. However, recently you observed a jackal alerting a tiger to a kill with a loud cry. If you continue to observe this alerting behavior, you might change the categorization of the jackal/tiger relationship from to .

commensalism; mutualism                          

Explanation:

Commensalism: The term "commensalism" is described as a "long-term" biological interaction whereby different members of a specific species gains or discovers benefits whereas members of other species neither gets harmed nor benefited.

Mutualism: The term "mutualism" is described as the "ecological interaction" between two or more than two species whereby each species possesses a "net benefit".

In the question above, the given statement represents commensalism and mutualism.

i would say b. research typically uses a variety of sources