Some scientists believe that the relationship between mice and humans has, over time, diminished the ability of mice to survive in nature, so that now they must depend upon human civilization for their continued existence. This opinion, however, ignores significant facts. Despite numerous predators and humanity' s enmity, mice have distributed themselves more widely across the planet than any other mammal except humans. Mice reproduce rapidly and, more important to their survival, they have the ability to adapt to an extraordinary range of habitats. Should the environment ever become too extreme to support human life, naturalists predict that mice would be able to adapt and survive. Which one of the following, if true, would most support the naturalists' prediction? ['Fossil remains prove that mice inhabited North America prior to the arrival of humans.', 'Mice have colonized an island near Antarctica which is too bleak and harsh to support human life.', 'Under optimum conditions, mice reproduce every four weeks, with five to seven pups per litter.', 'The size of the mouse population is limited by the availability of food.']