Boreal owls range over a much larger area than do other owls of similar size. Scientists have hypothesized that <b> it is scarcity of prey that leads the owls to range so widely. </b>This hypothesis would be hard to confirm directly, since it is not possible to produce a sufficiently accurate count of the populations of small mammals inhabiting the forests where boreal owls live. Careful study of owl behavior has, however, shown that <b> boreal owls do range over larger areas when they live in regions where food of the sort eaten by small mammals is comparatively sparse. </b> This indicates that the scientists' hypothesis is not sheer speculation. In the argument given, the two <b> boldfaced </b> portions play which of the following roles? ['The first describes a position that the argument opposes; the second states the main conclusion of the argument.', 'The first presents an explanatory hypothesis; the second presents evidence tending to support this hypothesis.', 'The first presents an explanatory hypothesis; the second presents evidence to support an alternative explanation.', 'The first describes a position that the argument opposes; the second presents evidence to undermine the support for the position being opposed.']