Answer:
The scientist should observe the species in the environment to determine the types of interactions that the two species have. Then, the scientist should transplant each species alone to a new area and simultaneously transplant both species together to see if the single-species transplants die
Step-by-step explanation:
When two species are obligate mutualists, both species benefit one another in such a way that one cannot survive without the other. Hence, in order to find out if two species are indeed obligate mutualists, they should be transplanted together away from other species on one side, and also transplanted individually on another side.
If they are obligate mutualists, the individual transplant would find it difficult to survive and should die in no time while the transplant done together should survive. All other factors being kept constant.