Critical Reasoning

Over the last century, paleontologists have used small differences between fossil specimens to classify triceratops into sixteen species. This classification is unjustified, however, since the specimens used to distinguish eleven of the species come from animals that lived in the same area at the same time.

Which of the following, if true, would enable the conclusion of the argument to be properly drawn?

(A) Not every species that lived in a given area is preserved as a fossil.
(B) At least one individual of every true species of triceratops bas been discovered as a fossil specimen.
(C) No geographical area ever supports more than three similar species at the same time.
(D) In many species, individuals display quite marked variation.
(E) Differences between fossil specimens of triceratops that came from the same area are no less distinctive than differences between specimens that came from different areas.

Please explain each of the choices OA Later

The question can be broken down as follows:

1. Premise: 16 species were classified by differences in fossils
   Premise: 11 of them were of the same area and time
   Supporting premise: ?
   Conclusion: the classification is incorrect

Answer choice C completes the argument in the most direct way - it undermines the classification made by the paleontologists by showing it cannot possibly be true, connecting well with the second premise.

Notice that answer choice D also undermines the paleontologists' classification by saying small differences can be found not only in separate species but also in a single species. However, this is less direct than the aforementioned answer choice, and does not work with the second premise.

can someone tell why E is wrong

thanks in advance

winner's attitude wrote:can someone tell why E is wrong

thanks in advance

When you break this down the argument is that using multiple specimens from the same area is not an accurate way to classify species.

E really has nothing to do with that, but what you have to do is recognize that E is talking about different areas. Go back to the conclusion and read the following

since the specimens used to distinguish eleven of the species come from animals that lived in the same area at the same time

Those words mean the argument is based on a specific location and time. Now go to choice E.

(E) Differences between fossil specimens of triceratops that came from the same area are no less distinctive than differences between specimens that came from different areas.

Other areas is totally out of scope of the argument and would be a different argument altogether

When you go to choice C you can pick out the following words:

(C) No geographical area ever supports more than three similar species at the same time.

That means the same area and at the same time, which brings us back to the original argument in the passage almost word for word. The number 3 is also important there since he makes a point that 11 species were from the same area.

I don't see E as out of scope: on the contrary, it would weaken the line of reasoning