[求助]LAST 6-2-12

12. 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 postglacial 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 then many warm-weather plants.

答案是E这一题看得糊里糊涂的，谁能告诉我ABCD     是怎么解释这个矛盾现象的？多谢了