I have a question regarding the captioned exercise. I understand that the answers are deliberately twisted by the authors so it is not representative of how actual LSAT questions would be set, but I would like to know why my choice of answer was deemed incorrect by the authors nonetheless.
Here comes the relevant except:
A growing temperature differential between the unusually cool middle and high latitudes and the warm tropical latitudes is causing a southward expansion of the circumpolar vortex
Question:
According to the passage, which of the following, if occurs, would likely to cause the circumpolar vortex to expand?
Possible answer choices are as follows:
(A) There is a growing temperature differential between the middle and tropical latitudes.
(D) There is a significant increase in the difference between the average annual atmospheric temperature of the tropics and that of the more northern latitudes.
The authors of the book rightly eliminated B, C and E, but go on to state that D included all latitudes whereas A only mentioned tropical and middle latitudes and therefore D is the correct answer.
While I think what the authors considered are correct, D also introduced the idea of a "significant" increase, which is nowhere to be found in the relevant excerpt, thus i thought that it is guilty of an incorrect degree.
On the other hand, I thought that A's word-for-word description of the event in terms of degree is more important than A's omission of the polar latitudes, as it can be inferred that if there is a growing difference in temperature between the tropical and middle latitudes, surely the temperature difference between polar and tropical latitudes would also increase. The original piece did not made any comparison between the middle latitudes and polar latitudes, thus there is nothing wrong with omitting them in A.
Obviously I was not convinced by the author's decision as the book did not elaborate on the degree issue as mentioned above. I wonder if anyone can shed me some light on this issue?
Thanks in advance!