Scientists once believed that the oversized head, long hind legs, and tiny forelimbs that characterized Tyrannosaurus...

Irina on August 30, 2019

@ali,

Let's look at the argument.

The passage starts off with a hypothesis that certain features of T-rex developed to accommodate the great size and weight of this predator. The passage then cites the evidence of a recently discovered earlier dinosaur skeleton with the same features but one-fifth the size and one-hundredth of T-rex weight, i.e. a mini T-rex version, to conclude that this hypothesis is wrong.

What information do we need to conclude that the argument follows logically?

Let's think about it. The skeleton belonged to an earlier dinosaur - not T-rex - and the author concludes that because it had the same features but no need to accommodate the great size and weight, there must be an alternative explanation for these physical characteristics that this skeleton and T-rex share. (B) makes us question this assumption by asking "At what stage of life did the recently discovered specimen die?" If this is a juvenile dinosaur that failed to reach its adult size and weight, the hypothesis that these physical characteristics developed to accommodate greater weight and height could still hold true. We thus need this additional information to determine if this new evidence is sufficient to refute the T-rex hypothesis.

Does this make sense?

Let me know if you have any further questions.

Meredith on October 23, 2019

I understand your explanation but how can you rule out the other answer choices?

shunhe on December 22, 2019

(A) - the body size isn't relevant when we consider the argument, and the language ("the same") is a bit extreme.

(C) - other, larger dinosaurs are irrelevant to what we can learn about the T Rex.

(D) - relationship of the T Rex to other species is irrelevant to the biology and physics of the T Rex itself.

(E) - Irrelevant, their food choices won't tell us about the physics of their anatomy.

Hope this helps.

kens on August 18, 2020

D: Was the species to which the recently discovered dinosaur belonged related to T. rex? What if the answer to this question is no, and we thereby conclude that the recently discovered dinosaur, though having similar features, is no a T-rex? I might be misinterpreting the answer choice, but please help me understand. Thanks in advance!

on May 24, 2022

^^^^

Emil-Kunkin on May 24, 2022

Hi,

If species are related tells us very little about them. Rats and capybaras are related, yet the former are way smaller than the latter, so are cats and tigers. However, there are also a lot of species who are related that are similar in size. The word "related" is pretty useless, as we have no idea what it means. We could argue that all dinosaurs are related to the T-rex, as they all evolved from a common ancestor.