Review this scenario. Rainbow trout are a freshwater fish native to streams and lakes along the western coast of North America. While studying streams in the eastern United States, an ecologist noticed that rainbow trout were abundant in the ecosystem, but other native species of fish were almost entirely missing. She also observed lower populations of macroinvertebrates. The ecologist wondered why there were so few native fish species and macroinvertebrates. By reading ecological reports of the area, the scientist learned that rainbow trout had been introduced to the streams for sport fishers to catch. Initially, 100 fish had been introduced, but the ecologist conducted a field survey and estimated that over 1,000 rainbow trout now lived in the streams. She also read from other studies that rainbow trout feed primarily on macroinvertebrates. Which question most closely relates to the ecologist's observations and the collected scientific data on river ecosystems? Do the native fish species have a disease? Are rainbow trout displacing native species by outcompeting them for food? Did pollution kill off the native fish species? Why are there so many rainbow trout in the streams?