Archaeologists seeking the location of a legendary siege and destruction of a city are excavating in several possible places, including a middle and a lower layer of a large mound. The bottom of the middle layer contains some pieces of pottery of type 3, known to be from a later period than the time of the destruction of the city, but the lower layer does not.
The force of the evidence cited above is most seriously weakened if which of the following is true?

Question

Examsnet · Accepted Answer

Correct Answer is :  Gerbils, small animals long native to the area, dig large burrows into which objects can fall when the burrows collapse.

GMAT Verbal Reasoning Practice Test 3