#10 - People who are allergic to cats are actually allergic

[Administrator]

Complete Question Explanation

Must Be True. The correct answer choice is (C)

This stimulus is a basic Fact Set: Those who have cat allergies are specifically allergic to proteins
that are secreted through the skin and saliva, but the kind of proteins that draw such reactions vary
from person to person. Every cat sheds skin and saliva, which means that every cat can elicit an
allergic reaction, but cats often elicit such reactions in some with allergies and not others.

Since the stimulus is a collection of facts with no real argument, it is unsurprisingly followed by a
Must Be True question, which means that the correct answer choice must pass the Fact Test, and will
be confirmed by the information from the stimulus.

Answer choice (A): Although the author does say that cats often elicit allergic reactions in some
allergy sufferers and not others, the information in the stimulus is limited to people who are allergic
to cats. Since the language in this choice is overly broad, it is not supported by the stimulus and fails
the Fact Test.

Answer choice (B): The stimulus provides that many cats can bring about allergic reactions in some
people and not others, but that doesn’t mean that no cat has such broad-based allergy-provoking
proteins. There is no information in the passage that precludes the existence of a cat that elicits
reactions in all allergy sufferers, so this choice is unsupported by the passage and should be ruled out
of contention.

Answer choice (C): This is the correct answer choice. The author provides that cats can commonly
elicit allergic reactions in some allergy sufferers and not others. Combined with the fact that these
allergies are caused by specific proteins in the skin and saliva, this supports the inference that these
proteins must vary among cats.

Answer choice (D): The author of the stimulus does not mention the intensity level of various
allergic reactions, so while this choice could be true, it cannot be said that it must be true, so this
answer fails the Fact Test and should be ruled out of contention.

Answer choice (E): The stimulus contains no mention of whether various allergic reactions might be
predictable, so this answer cannot be confirmed by the information from the stimulus.

[e.bryant]

Dec 12 LSAT, Section 2, Q10.

This is a Must Be True question, I think. I had no doubt in mind when I was taking the test that I got this one correctly. To my surprise the correct answer choice was C and not E. I have read it over and over again and I cannot seem to understand why C is the strongest answer choice. We are told that all cats shed skin and spread saliva and that there are certain proteins in them to which people are allergic. It is unknown, however, which particular protein is responsible and that varies from allergy suffered to allergy sufferer. If all cats are capable of producing allergic reactions, then I got to the conclusion that, indeed, there is no way to predict whether a given cat will produce an allergic reaction in particular allergy sufferer (E) because we simply don't know which particular protein is this particular sufferer allergic to. How do we know that not all cats are identical with respect to the proteins they contain (C)? All we know from the stimulus is that they all have some proteins in their skin and saliva. Whether these proteins are identical or not, would not affect the fact that different allergy sufferers would be affected by different proteins, and therefore it's not possible to predict if a given cat will cause allergies to particular person.

Phew, I am exhausted from typing : ) Sorry about the long post, I wanted to let you know the particular reasons I picked certain answer choices over others. Usually I don't face much difficulty in recognizing why an answer choice is correct after I read the question a few times, but these 2 questions are just killing me.

Thank you!

[Steve Stein]

Hi,

Good question: that stimulus is a basic Fact Set: Those who have cat allergies are specifically allergic to proteins that are secreted through the skin and saliva, but the kind of proteins that draw such reactions vary from person to person. Every cat sheds skin and saliva, which means that every cat can elicit an allergic reaction, but cats often elicit such reactions in some with allergies and not others.

The issue with answer choice E is that the stimulus contains no mention of whether various allergic reactions might be predictable, so this answer cannot be confirmed by the information from the stimulus.

Answer C is the correct answer choice; the author provides that cats can commonly elicit allergic reactions in some allergy sufferers and not others. Combined with the fact that these allergies are caused by specific proteins in the skin and saliva, this supports the inference that these proteins must vary among cats.

I hope this is helpful! Please let me know whether this is clear--thanks!

~Steve

[e.bryant]

Thank you, Steve. This was very helpful! I even drew a hypothetical scenario with 2 allergy sufferers and 2 cats with different proteins to test C. It checks out For the sake of time though, I should have focused on the "predict" in E and eliminate it right away.

Thank you again!

[Nekrowizard]

People who are allergic to cats...

Credited answer is C, and it's definitely the best out of all the choices. But the stimulus line about which particular proteins are responsible varying between allergy sufferers bothers me. The way it's phrased makes it sound to me as if all cats secrete the same proteins while people have differing protein receptors, causing them to react differently. Is there any particular reasoning that my thinking is wrong, aside from it not being features in any of the answer choices?

[Ron Gore]

Hi, Nekrowizard. Thanks for your question!

You asked whether the stimulus supports the inference that "all cats secrete the same proteins while people have differing protein receptors, causing them to react differently," and whether this inference could also have been the subject of a correct answer choice this Must Be True question.

The answer is no, that is not an inference permissible from the stimulus. If all cats secrete the same proteins, then every cat would cause an allergic reaction in all people who are allergic to cats. It would simply be that various people are reacting to different proteins secreted by the cat. However, the last sentence is inconsistent with this possibility, stating "it is common for a given cat to cause an allergic reaction in some—but not all—people who are allergic to cats."

In fact, answer choice (C), the correct answer choice, reflects that your proposed inference is not permitted by the stimulus. It says that "not all cats are identical with respect to the proteins contained in their skin secretions and saliva." This is the opposite of your inference, and shows that it was in fact tested, but in the sense that it is excluded as a Must Be True inference.

If I've mistaken the proposed inference in your question or if I can be of further assistance, please let me know.

Thanks,

Ron

[15veries]

Hi,

I thought B is very attractive.
Is B wrong because in the stimulus it says "common"?
So saying "No" is too strong

[Emily Haney-Caron]

15veries,

Yep, sounds like you answered your own question with this one. The more you can do that, the stronger your confidence and abilities will become, so make sure you're always taking time to really work through questions on your own (going back to them three or four times over a couple of days) before you post, so you can be sure you're really stuck. That will help you get the most out of your studying!

[ally.ni]

If answer choice included only allergy sufferers, would that answer choice be correct?

[Adam Tyson]

Assuming that you're asking about answer A here, ally.ni, that wouldn't make it any better, because there's no evidence that any allergy sufferer is allergic to entire breeds of cats, but only that they are allergic to at least some cats. So one allergy sufferer could be allergic to a certain cat of a certain breed, but not allergic to another cat of the same breed.