Question ID:PT89 S4 Q10 Passage:Many species of plants produce nectars known as extrafloral nectories (EFNs), which are known to attract certain ants that defend the plants against leaf-eating insects. Recently, greenhouse experiments have found that jumping spiders jump onto plants with active EFNs six times more often than they jump onto plants without EFNs, and regularly eat the nectar. So, like the ants, jumping spiders apparently defend EFN-producing plants against leaf-eating insects. Stem:Which one of the following, if true, would most strengthen the argument above? Correct Answer Choice:BChoice A:For many species of nectar-producing plants, productivity is increased when a plant is protected from leaf-eating insects. Choice B:In field experiments, the introduction of jumping spiders into an environment was followed by a significant increase in the population of EFN-producing plants. Choice C:Some species of EFN-producing plants cannot survive without some outside agent protecting them from leaf-eating insects. Choice D:Experiments with types of spiders other than jumping spiders suggest that these other types of spiders do not defend EFN-producing plants. Choice E:Regions with large populations of ants also tend to have large populations of EFN-producing plants.