Which of the following, if true of the cave, most weakens the argument? A. Some of the plant species found in the earlier (lower) levels of habitation are not found at all in the later (upper) levels of habitation. B. The remains of some plant species, such as squash and chili peppers, show changes from the middle to the later (upper) levels that indicate domestication. C. At certain points during the period from 9,000 to 500 years ago, the cave was abandoned for a time and later reoccupied by people who were probably of a different culture than the earlier inhabitants D. Virtually all the plant remains found at earliest (lowest) levels of habitation are tough fibers that are relatively resistant to decomposition. E. The total volume of food plant remains found in the earlier (lower) layers was greater than that found in the later (upper) layers.