Akela
Paleontologist: Plesiosauromorphs were gigantic, long-necked marine reptiles that ruled the oceans during the age of the dinosaurs. Most experts believe that plesiosauromorphs lurked and quickly ambushed their prey. However, plesiosauromorphs probably hunted by chasing their prey over long distances. Plesiosauromorph fins were quite long and thin, like the wings of birds specialized for long-distance flight.
Which one of the following is an assumption on which the paleontologist’s argument depends?
(A) Birds and reptiles share many physical features because they descend from common evolutionary ancestors.
(B) During the age of dinosaurs, plesiosauromorphs were the only marine reptiles that had long, thin fins.
(C) A gigantic marine animal would not be able to find enough food to meet the caloric requirements dictated by its body size if it did not hunt by chasing prey over long distances.
(D) Most marine animals that chase prey over long distances are specialized for long-distance swimming.
(E) The shape of a marine animal’s fin affects the way the animal swims in the same way as the shape of a bird’s wing affects the way the bird flies.
Source: LSAT
In assumption questions, it is important to identify the premise and conclusion since our assumption will link the premise and conclusion.
Premise: Plesiosauromorph fins were quite long and thin, like the wings of birds specialized for long-distance flight
Conclusion: plesiosauromorphs probably hunted by chasing their prey over long distances
A - The fact that birds and reptiles share many physical features is irrelevant to the argument. This does not address the specific feature of wings
B - The fact that P is the only marine reptiles that had long, thin fins is irrelevant to the argument.
C - This may strengthen the conclusion, but does not address the link between the premise and the conclusion. The answer says nothing about how the fins of P is similar to the wings of birds that allow birds to fly long distance. This answer is actually irrelevant
D - Similar to C, this does not address the link between the premise and the conclusion
E - Correct. The answer notes that shape of marine's fins affects the way an animal swims in the same way as the shape of a bird’s wing affects the way the bird flies. If fins DO NOT affect how marine animal swims the same way bird's wings affects the way the bird flies, then the premise cannot be used to support the conclusion that P chased prey over long distances