Nutritionist: Because humans have evolved very little since the development of agriculture, it is clear that humans are still biologically adapted to a diet of wild foods, consisting mainly of raw fruits and vegetables, nuts and seeds, lean meat, and seafood. Straying from this diet has often resulted in chronic illness and other physical problems. Thus, the more our diet consists of wild foods, the healthier we will be. The claim that humans are still biologically adapted to a diet of wild foods plays which one of the following roles in the nutritionist's argument? ['It is a conclusion for which the only support offered is the claim that straying from a diet of wild foods has often resulted in chronic illness and other physical problems.', "It is a phenomenon for which the main conclusion of the nutritionist's argument is cited as an explanation.", "It is an intermediate conclusion for which one claim is offered as support, and which is used in turn to support the argument's main conclusion.", "It is a premise for which no justification is provided, but which is used to support the argument's main conclusion."]