The Aquipos toucan is able to use its long beak to reach inside apertures in a tree's bark and feed on the insects that dwell within and that are the toucan's main food source. Several noted ornithologists have speculated that because the toucan's beak is curved in a manner similar to the openings in the bark, the beak evolved so that the toucan can best take advantage of the insects lying deep inside. Which of the following, if true, argues most strongly against the ornithologists' speculation? ['The Aquipos toucan is also able to use its beak to break bark, thereby accessing insects that dwell in the trunk.', 'Many insects crawl on the bark of the tree and a toucan can sometimes become satiated without having to access insects living beneath the bark.', 'The tree holes in which the Aquipos toucan is able to access insects have a characteristic shape that differs only very slightly from tree to tree.', "Not all trees in the Aquipos toucan's environment house sufficient quantities of insects to satisfy the caloric needs of the toucan."]