Scientists once believed that the oversized head, long hind legs

Question

Scientists once believed that the oversized head, long hind legs, and tiny forelimbs that characterized  Tyrannosaurus rex  developed in order to accommodate the great size and weight of this prehistoric predator. However, this belief must now be abandoned. The nearly complete skeleton of an earlier dinosaur has recently been discovered. This specimen had the characteristic  T. rex  features but was one-fifth the size and one-hundredth the weight.

The answer to which one of the following questions would most help in evaluating the argument?

(A) Was the ratio of the head size of the recently discovered dinosaur to its body size the same as that for  T. rex ?

(B) At what stage in its life did the recently discovered dinosaur die?

(C) Was  T. rex  the largest and heaviest prehistoric predator?

(D) Was the species to which the recently discovered dinosaur belonged related to  T rex ?

(E) Did the recently discovered dinosaur prey on species as large as those that  T rex  preyed on?

Source: LSAT 80, December 2016

GMATNinja · Accepted Answer

It doesn't matter whether the recently discovered dinosaur is actually RELATED to the T Rex. The author is trying to question a belief about the FEATURES of the T. Rex, and we are told that the "specimen had the characteristic T. rex features." Thus, this related dinosaur can be used as evidence against the commonly held belief.

However, it is possible that the recently discovered skeleton was that of a baby or young dinosaur that would eventually grow to be about as large as an average T-Rex. In that case, the recently found skeleton would not serve as evidence against the commonly held belief. Thus, answering the question posed in choice (B) would be the most useful in evaluating the argument.

niks18 · Answer

The argument states that the recently discovered skeleton does not match the features of  T rex  hence the earlier believed features of  T rex  must not be true. to corroborate this fact we must know more about skeleton's feature as whether the skeleton was of a full grown up animal or was it of a young animal.

(A) Was the ratio of the head size of the recently discovered dinosaur to its body size the same as that for  T. rex ?------ irrelevant. we want to establish whether  T rex  had oversized head and other features based on the skeleton

(B) At what stage in its life did the recently discovered dinosaur die?------- Correct. The answer to this question will provide information regarding the age of the discovered dinosaur which is crucial in determining height and weight

(C) Was  T. rex  the largest and heaviest prehistoric predator?--------- this will not provide any relation between the discovered skeleton and  T rex

(D) Was the species to which the recently discovered dinosaur belonged related to  T rex ?------ Irrelevant. This information will not link the discovered skeleton to  T rex  features

(E) Did the recently discovered dinosaur prey on species as large as those that  T rex  preyed on?------ Irrelevant information

akela · Answer

One of the ways to deal with this kind of CR is to give opposite answers to the question:

(B) Early stage - than it might be T.rex at early stage of its life, i.e. the same species - weakens the argument
Adult stage - then it belongs to different species - strengthens the scientists' argument

doeadoer · Answer

Is it not important to find out if this recently discovered dinosaur is indeed related to t Rex as suggested in D. could someone help with this question

NNURP · Answer

A) Was the ratio of the head size of the recently discovered dinosaur to its body size the same as that for T. rex?
The ratio is not affect the statement at all. Even the ratio is the same, but who knows if it grows into different ratio.

(B) At what stage in its life did the recently discovered dinosaur die?
Correct - we know the stage of dinosaur then we can make the judgement whether the theory holds.

ravigupta2912 · Answer

Didn't read choice B correctly so marked A (trap choice). But on second read, B is absolutely correct. Since if you apply the evaluate framework i.e. consider the two extreme answers, the argument shatters in one of the answers (early stage).

Jaffer99 · Answer

Can someone please explain why the answer is not D? Shouldn't it matter whether the Dinosaur is even somewhat from the same species?

Scientists once believed that the oversized head, long hind legs

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Scientists once believed that the oversized head, long hind legs

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