Reading Comprehension
试题详情
文章：
| Line | Resin is a plant secretion that hardens when |
| exposed to air; fossilized resin is called amber. | |
| Although Pliny in the first century recognized that | |
| amber was produced from “marrow discharged by | |
| (5) | trees,” amber has been widely misunderstood to be |
| a semiprecious gem and has even been described | |
| in mineralogy textbooks. Confusion also persists | |
| surrounding the term “resin,” which was defined | |
| before rigorous chemical analyses were available. | |
| (10) | Resin is often confused with gum, a substance |
| produced in plants in response to bacterial infections, | |
| and with sap, an aqueous solution transported | |
| through certain plant tissues. Resin differs from both | |
| gum and sap in that scientists have not determined a | |
| (15) | physiological function for resin. |
| In the 1950s, entomologists posited that resin | |
| may function to repel or attract insects. Fraenkel | |
| conjectured that plants initially produced resin in | |
| nonspecific chemical responses to insect attack | |
| (20) | and that, over time, plants evolved that produced |
| resin with specific repellent effects. But some insect | |
| species, he noted, might overcome the repellent | |
| effects, actually becoming attracted to the resin. | |
| This might induce the insects to feed on those | |
| (25) | plants or aid them in securing a breeding site. |
| Later researchers suggested that resin mediates | |
| the complex interdependence, or “coevolution,” of | |
| plants and insects over time. Such ideas led to the | |
| development of the specialized discipline of chemical | |
| (30) | ecology, which is concerned with the role of plant |
| chemicals in interactions with other organisms and | |
| with the evolution and ecology of plant antiherbivore | |
| chemistry (plants’ chemical defenses against attack | |
| by herbivores such as insects). |
题目：
The author refers to “bacterial infections” (see line 11) most likely in order to
选项:
A、describe the physiological function that gum performs in plants
B、demonstrate that sap is not the only substance that is transported through a plant’s tissues
C、explain how modern chemical analysis has been used to clarify the function of resin
D、show that gum cannot serve as an effective defense against herbivores
E、give an example of how confusion has arisen with regard to the nature of resin
答案:
A
