The Levant -- the area that borders the eastern Mediterranean-was heavily populated in prehistoric times. The southern Levant was abandoned about 6, 000 years ago, although the northern Levant, which shared the same climate, remained heavily populated. Recently archaeologists have hypothesized that the sudden depopulation in the southern Levant was due to an economic collapse resulting from deforestation. If the statements above are true and the archaeologists' hypothesis is correct, which one of the following CANNOT be true? ['The sheep and goats herded by the peoples of the southern Levant until 6, 000 years ago grazed extensively on the seedlings and saplings of indigenous tree species.', 'Carbon dating of organic remains from the southern Levant reliably demonstrates that there were no forests present in that area prior to 6, 000 years ago.', 'Organic remains from the northern Levant reliably indicate that tree species flourished there without interruption during the period when the southern Levant was being abandoned.', 'Since there are few traces of either quarried stone or of mud brick in buildings excavated in the southern Levant, it is likely that the buildings built there prior to 6, 000 years ago were made almost entirely of timber.']