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| 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). |
According to the passage, which of the following is true of plant antiherbivore chemistry?
答案：A
