#22 - Scientists once believed that the oversized head, long

[Dana D]

Hey Will,

We want to look at the argument (conclusion) the author uses here - we have to abandon the idea that T Rex developed into their shape because of their size and weight because of the new dino skeleton found. The stimulus already implies this skeleton is not that of a T rex - it's an "earlier dinosaur." So that means answer choice (D) would not help us in evaluating the argument.

Instead, we would want to ask (B), what stage of life did the dinosaur die at? If this dino was a fully grown adult, then it makes sense to say the size and weight was not relevant to why the T rex has a big head and tiny arms because this dinosaur has those same features, but it is small.

However, if the dinosaur died as an adolescent, maybe it would have grown to the T rex's full size and weight as an adult, and the scientists' original hypothesis would still stand.

Hope that helps!

[willwants170]

Hey Will,

We want to look at the argument (conclusion) the author uses here - we have to abandon the idea that T Rex developed into their shape because of their size and weight because of the new dino skeleton found. The stimulus already implies this skeleton is not that of a T rex - it's an "earlier dinosaur." So that means answer choice (D) would not help us in evaluating the argument.

Instead, we would want to ask (B), what stage of life did the dinosaur die at? If this dino was a fully grown adult, then it makes sense to say the size and weight was not relevant to why the T rex has a big head and tiny arms because this dinosaur has those same features, but it is small.

However, if the dinosaur died as an adolescent, maybe it would have grown to the T rex's full size and weight as an adult, and the scientists' original hypothesis would still stand.

Hope that helps!

Yes, I agree with the reasoning of B and D, but doesn't B have to assume the earlier fossil is related to the T. rex, or it wouldn't be able to evaluate the argument. Through analogy, let's assume our human physiology is built like this because of our need to drink water. If we find fossils similar to humans but smaller in scale and lighter in weight at Mars one day but genetically unrelated to us, we can't use them to make conclusions about us as a species because they are not our species. However, through my STEM background, I know that many similarities across different species are the result of evolution towards the same goal, so considering that, I could pick B. Maybe the dinosaurs are unrelated but similar physiology means similar goal, to accommodate the weight and size. Does LSAC expect us to have this background?

[Luke Haqq]

Hi willwants170!

To your first question, it doesn't seem like (B) has to assume that the earlier fossil is related to the T. rex. Even if it was a different type of dinosaur, it was similar in certain respects noted in the stimulus (legs, forelimbs, and head). Yet it was also different in its size and weight. This might seem to suggest that the size and weight may not be the reason that those features developed. However, before getting to that, it'd be important to know how old the new specimen was when it died. As Dana notes, it could have died in childhood and might have otherwise developed to have a similar weight and size to the T. Rex.

To your second question, the LSAC does not expect test takers to have a STEM background or any other particular area of expertise. If any STEM concepts are relevant to the right answer choice on a logical reasoning question, all the necessary information for arriving at the correct answer will be contained within the stimulus. Similarly, STEM concepts might very well appear in the reading comprehension section, but that section will only test what is contained within the specific passages provided.