The speaker raises couterarguments against the reading passage by providing drastically different evidence regarding the vanishment of Anasazi from New Mexico's Chaco Canyon around 1130 A.D.
Firstly, the reason that global warming led to the disappearent of New Mexico's Chaco Canyon which insisted by the writer was opposed by the speaker. who provid the evidence that the global warming did not seriously influence the inhabitents' living condition, since the trees were still alive at that time.
Secondly,while the writer states that it was the water shortage that cause the leaving of the Anasazi, the lecturer opposes the claim, provide an explanation that the Anasazi was used to the drought and had been always have the habit to save some crops in case of thr starvation.This is another part that the auter was doubted by the lecture.
Thirdly, the auter puts forward a suggestion that the Anasazi was suffered the shortage of food, for the big summer drought, which the professor denies with the proof that they are attacked by other trib, not because of teh shortage of food.From this case, the motion of writeris totally impoper.