Answer:
(D) There is pollution in the East river that the Yellow Perch are adapted to but the Walleye are not.
Step-by-step explanation:
To ensure survival and cntinurd sustenance in an environment, there is need for an animal to posses certain features which would enable her cope with the conditions of the environment. The ability of animals to successfully live and survive in an environment is made possible through adaptation as the animal's adaptive features ensures the animal is able to live through and cope. If the adaptive features aren't suitable for such environment, then migration has to occurs, leading the animal to find a more suitable environment for survival. In the scenario above, the East river was presumed to be a good habitat for the Walleye and Yellow Perch, in spite of the available and abundance of food, the Walleye migrated, which is most likely due the fact that the Walleye lack the adaptive features to survive in the East river probably due to pollution which the Yellow Perch is well adapted to.