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 bytrees,” 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. 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 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 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 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 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?
Changes in a plant's antiherbivore chemistry may affect insect feeding behavior.
A plant's repellent effects often involve interactions between gum and resin.
A plant's antiherbivore responses assist in combating bacterial infections.
Plant antiherbivore chemistry plays only a minor role in the coevolution of plants and insects.
Researchers first studied repellent effectsin plants beginning in the 1950s.
发展过程：nonspecific response → specific repellent effect → 调节植物和昆虫的共同进化。
文章细节题：关于plant antiherbivore chemistry（PAC），以下哪点是对的？