36. Which of the following statements best expresses the main idea of the passage? (A) Recurring outbreaks of infestation by gypsy moth caterpillars have had a devastating impact on trees in the northeastern United States. (B) A mechanism used by trees to combat the threat from gypsy moth caterpillars has actually made some trees more vulnerable to that threat. (C) Although deadly to gypsy moth caterpillars, wilt disease has failed to significantly affect the population density of the caterpillars. (D) The tree species with the highest levels of phenols in their foliage are the most successful in defending themselves against gypsy moth caterpillars.