Critical Reasoning

By dating fossils of pollen and beetles, which returned after an Ice Age glacier left an area, it is possible to establish an approximate date when a warmer climate developed. In one glacial area, it appears from the insect record that a warm climate developed immediately after the melting of the glacier. From the pollen record, however, it appears that the warm climate did not develop until long after the glacier disappeared.

Each one of the following, if true, helps to explain the apparent discrepancy EXCEPT:

(A) Cold-weather beetle fossils can be mistaken for those of beetles that live in warm climates.
(B) Warm-weather plants cannot establish themselves as quickly as can beetles in a new environment.
(C) Beetles can survive in a relatively barren post glacial area by scavenging.
(D) Since planes spread unevenly in a new climate, researchers can mistake gaps in the pollen record as evidence of no new overall growth.
(E) Beetles are among the oldest insect species and are much older than many warm-weather plants.

OA: E

Why not A

neeti2711 wrote:By dating fossils of pollen and beetles, which returned after an Ice Age glacier left an area, it is possible to establish an approximate date when a warmer climate developed. In one glacial area, it appears from the insect record that a warm climate developed immediately after the melting of the glacier. From the pollen record, however, it appears that the warm climate did not develop until long after the glacier disappeared.

Each one of the following, if true, helps to explain the apparent discrepancy EXCEPT:

(A) Cold-weather beetle fossils can be mistaken for those of beetles that live in warm climates.
(B) Warm-weather plants cannot establish themselves as quickly as can beetles in a new environment.
(C) Beetles can survive in a relatively barren post glacial area by scavenging.
(D) Since planes spread unevenly in a new climate, researchers can mistake gaps in the pollen record as evidence of no new overall growth.
(E) Beetles are among the oldest insect species and are much older than many warm-weather plants.

OA: E

Why not A

Imagine you're a scientist. You're trying to account for the fact that one of your colleagues found a beetle that suggests the climate began to warm in one year, and another colleague found some pollen that suggests the climate began to warm much later. If the colleague who found the beetle found a cold-weather beetle but thought she'd found a warm-weather, she'd mistakenly believe that the climate had begun to warm when, in fact, it hadn't. In other words, the colleague who found the beetle may have goofed. This could account for the discrepancy between your colleagues' conclusions.