Prep2012-Pack1-CR-034 VCR001296 Medium
Reasoning
Given the facts stated, what would make the dolphin calf deaths more likely to have resulted from toxins in their mother’s milk? The dolphins live in a polluted environment. Therefore, the mother dolphins are accumulating toxins in their body fat. Most of the toxins in a mother dolphin pass through her milk into her nursing calf. Since dolphin calves are much smaller than their mothers, the calves are especially vulnerable to the toxins. The high mortality rate among the calves is more likely to have resulted from the toxins in the milk if calves who drink more milk have been more likely to die.
A. Correct. Calves whose mothers died before weaning would have drunk less toxic milk than other calves did, on average.
B. If dolphins along the Florida's Gulf Coast accumulated toxins at no higher a rate than elsewhere, then their milk would contain no more toxins than elsewhere and thus would not be especially likely to cause an unusually high mortality rate.
C. Since dolphin calves presumably consume milk from the same mother as their do, this would suggest that some factor other than the milk caused the high mortality rate.
D. If the calves accumulate toxins more quickly from the environment than their mothers do, the high mortality might have resulted mainly from toxins in the environment, not from those in the milk.
E. The argument says nothing about other mammal species, therefore this information is irrelevant.
The correct answer is A.
Prep2012-Pack1-CR-035 VCR001345 Medium
Reasoning
What would suggest that hunting by humans may have contributed to the mammoths' extinction, even though no spearheads have been found among mammoth bones? Perkins argues that since no spearheads have been found among mammoth remains, human hunting must not have contributed to the mammoths’ extinction. Perkins's argument assumes that humans did not hunt mammoths mainly with weapons other than spears; that spearheads would be left among remains of any mammoths killed with spears; that paleontologists have found a fair number of mammoth remains; and that any spearheads left among the remains would likely stay with them and be discovered. Any statement that calls any of these assumptions into question would provide a reason to discount the evidence Perkins offers.
A. If humans did not hunt mammoths, then mammoth bones probably would not be found with other mammal bones around prehistoric settlements where humans ate other mammals. Therefore, this would be compatible with Perkins’ argument.
B. This strengthens Perkins’ argument by out a possible alternative explanation of why paleontologists have found no spearheads in mammoth remains.
C. The prehistoric humans could have eaten meat other than mammoths, and this does not explain how they could have hunted mammoths without paleontologists finding spearheads in mammoth remains.
D. Perkins already acknowledges that humans coexisted with mammoths in North America, and this does not explain how humans could have hunted mammoths without paleontologists finding spearheads in mammoth remains.
E. Correct. This explains how, despite the evidence Perkins offers, humans may well have hunted mammoths without leaving any spearheads for paleontologists to discover in mammoth remains.
The correct answer is E.
