Question ID:PT16 S3 Q18 Passage:Because dinosaurs were reptiles, scientists once assumed that, like all reptiles alive today, dinosaurs were cold-blooded. The recent discovery of dinosaur fossils in the northern arctic, however, has led a number of researchers to conclude that at least some dinosaurs might have been warm-blooded. These researchers point out that only warm-blooded animals could have withstood the frigid temperatures that are characteristic of arctic winters, whereas coldblooded animals would have frozen to death in the extreme cold. Stem:Which one of the following, if true, weakens the researchers’ argument? Correct Answer Choice:DChoice A:Today’s reptiles are generally confined to regions of temperate or even tropical climates. Choice B:The fossils show the arctic dinosaurs to have been substantially smaller than other known species of dinosaurs. Choice C:The arctic dinosaur fossils were found alongside fossils of plants known for their ability to withstand extremely cold temperatures. Choice D:The number of fossils found together indicates herds of dinosaurs so large that they would need to migrate to find a continual food supply. Choice E:Experts on prehistoric climatic conditions believe that winter temperatures in the prehistoric northern arctic were not significantly different from what they are today.