Question ID:PT52 S3 Q19 Passage:One theory to explain the sudden extinction of all dinosaurs points to "drug overdoses" as the cause. Angiosperms, a certain class of plants, first appeared at the time that dinosaurs became extinct. These plants produce amino-acid-based alkaloids that are psychoactive agents. Most plant-eating mammals avoid these potentially lethal poisons because they taste bitter. Moreover, mammals have livers that help detoxify such drugs. However, dinosaurs could neither taste the bitterness nor detoxify the substance once it was ingested. This theory receives its strongest support from the fact that it helps explain why so many dinosaur fossils are found in unusual and contorted positions. Stem:Which one of the following, if true, would most undermine the theory presented above? Correct Answer Choice:AChoice A:Many fossils of large mammals are found in contorted positions. Choice B:Angiosperms provide a great deal of nutrition. Choice C:Carnivorous dinosaurs mostly ate other, vegetarian, dinosaurs that fed on angiosperms. Choice D:Some poisonous plants do not produce amino-acid-based alkaloids. Choice E:Mammals sometimes die of drug overdoses from eating angiosperms.