In Europe, many large animal species, such as mammoths, became extinct soon after humans first migrated to the animals' areas of habitation. The spread of such extinctions closely followed the pattern of human migration. However, since humans tended to migrate to areas as the climate in those areas began to warm, the extinctions might have been precipitated by the climatic warming rather than by human migration. Which of the following, if true, provides the best evidence that it was human migration and not climatic change that precipitated the extinctions? ['Several periods of marked climatic warming have occurred in Europe, during which many large animal species that lived there became extinct.', 'Many animal species, such as deer and bison, continued to thrive in Europe even after humans migrated there.', 'Many animal species that became extinct in Europe survived longer in areas that were isolated from human populations but that experienced intense climatic warming.', 'Some large animals had become extinct in Europe even before humans migrated there.']