Q24 - The body of anyone

[ksemenya87]

I can't seem to understand why E is correct from the information given in the stimulus. Can somebody please explain this to me!

[giladedelman]

Thanks for the question.

Here we're being asked to make an inference based on some given statements. We're told that a week after being infected by virus X, the body starts producing antibodies that increase in number for about a year. Now there's a test that, by measuring the level of antibodies, can determine how long someone has had the virus.

(E) is correct. The test works by measuring how many antibodies someone's body has produced. But we're told that these antibodies only start showing up a week after infection. So if someone who has been infected by virus X for three days is tested by the new test, he won't exhibit infection because his body hasn't started producing the antibodies yet! So we can infer that "for a time" -- i.e., for a week -- anyone infected by the virus won't exhibit infection if tested by the antibody test.

(A) is out of scope. There's nothing here about defeating the virus.

(B) is out of scope. We have no idea whether there are other ways of identifying the virus.

(C) is out of scope. All we know is that antibodies are produced for virus X.

(D) is, at best, out of scope -- we don't know anything about someone being infected "indefinitely" -- but it also seems contradicted by the statement that antibodies stop increasing after about a year.

Does that clear this one up for you? Let me know if you have any more questions.

[redcobra21]

I just have a general question about this. I understand that (E) is the only answer that can be properly inferred from the fact set, but it doesn't strike me as a statement that would be the conclusion to this paragraph. Does it matter that the question asks "which one of the following conclusions"? With this question stem, are they looking for a proper conclusion or something that is just "must be true"? Thanks!

[cyt5015]

I just have a general question about this. I understand that (E) is the only answer that can be properly inferred from the fact set, but it doesn't strike me as a statement that would be the conclusion to this paragraph. Does it matter that the question asks "which one of the following conclusions"? With this question stem, are they looking for a proper conclusion or something that is just "must be true"? Thanks!

First, this is not a identifying conclusion or main point question which requires us to find the conclusion. This is a "most strongly supported or best supported" question. The stimulus only has several facts. This type of question differs from "must be true" question by showing some wiggling room. The statement here, answer E is not a must be true one. Can we infer that the test will absolutely, 100% fail during the first infection week? Not really, but in normal cases, the test will fail. This is why the question stem asks us to find "best supported" instead of "must be true".

[tommywallach]

Hey There,

Just to be clear, the question does ask about "the conclusion." But in answer to the question posed above, very often the correct answer to a "draw a conclusion" question is not very conclusive. Yes, you are welcome to translate it to simply: "Which of the following is most likely to be true."

Hope that helps!

-t

[Mab6q]

E is definitely the better choice, but what about C. I looked at C sort of as a necessary assumption, which I felt must be inferable. If body defenses can help fight infections and the antibodies are produced, that would suggest that the test would not provide us with the estimate.

Any thoughts?

P.S. I know this is an inference question but I figured an answer that was necessary might be supported by the passage.

[ohthatpatrick]

Remember when you're doing Inference (and Necessary Assumption ... and Reading Comp) to be super cautious about picking answers with these qualities:
- extreme wording
- comparative wording
- out of scope wording

In order to feel okay about (C), I would have to make peace with the word "only".

It is a Necessary Assumption that "antibodies are produced for at least some viral infections".

That's it.

There's no way we could say that antibodies are produced ONLY for viral infections. What did the passage tell us about bacterial infections or fungal infections? Nothing.

Furthermore, what did the passage tell us about certain infections "that cannot be fought by any other body defenses"? Nothing about that, either.

So (C) has an extreme term and an out of scope idea that we have no support for / information about.

Hope this helps.

[jadewzheng]

I eliminated E for a mis-interpretation issue and I thought I'd share it with others here:

At a first glance, I eliminated all the answers; then, it came down to between D and E. I eliminated E because I saw "exhibit infection" I immediately thought "oh, symptoms." This made the answer choice all the more confusing considering it finished with "if tested by the antibody test." On the grounds of confusion and "the stimulus said nothing about symptoms" and confusion, I eliminated E and went (rather irresponsibly) for D. And during my review, once I understood "exhibit infection" as "confirming this person has an infection," there was no doubt that E was the right answer.

I majored in Bio during undergrad, and ironically, despite my mediocre performance, somehow the bio knowledge still trips me over on the LSAT every here and now. I guess my lesson from this should be: 1) NEVER use info outside of the LSAT and 2) If the answer choice doesn't make sense, read it over--it has to!

[hayleychen12]

Hi there! first time posting

1) I know why e is the right choice but i'm still confused with choice d, because it seems like to me a necessary assumption that has to be assumed to make this logic flow( cuz, for example, if there is a limit on the number of antibodies, say the antibodies reaches its limitation in month 5, then you cannot accurately determine how long person has had the virus at all). Am i overthinking too much?

2) this question makes me feel unsure about the differences between necessary assumption and inference questions, will an answer choice containing necessary assumption be the right answer in an inference question?( cuz in chapter 1 of the Manhattan bytype it does say that "from a formal logic standpoint, the correct answer to a Must Be True question is the necessary condition...." ) i can tell them apart in some circumstances, but in some occasions like this one, it just got me

[ohthatpatrick]

There is a lot of overlap between Inference and Necessary Assumption, in the sense that in both cases the correct answer is an idea that was basically embedded in the meaning/logic of the paragraph.

The big difference:
Necessary Assumption questions are based on ARGUMENTS
Inference questions are based on STATEMENTS / INFORMATION / FACTS

When you read NA, you find the Conc and the supporting ideas, and you think about
1. What missing logical links/ideas are there?
2. What potential objections could be made to this argument?

When you read Inf, you're just reading facts and asking yourself, "Can I combine any of these facts to derive some Inference?"

You're way more likely to predict the eventual answer on Necessary Assumption, because the author will often have one glaring missing link separating her evidence from her conclusion.

With Inference, ANYTHING that can be derived from the facts would be a correct answer. So it's harder to pin down one specific inference that "should" be the right answer.

As for (D), the fact we are given is that
"antibodies will increase in number for the next year or so".

From that fact, can we derive the idea that
"someone infected with X will have their antibodies increase FOREVER"?

No way. We were only told that antibodies will increase for a year or so; it would be a huge leap to suddenly infer "they will increase forever".

It's basically like this:
"Bob, how much longer do you think you'll take karate classes?"
-----"For another year or so."
"Whoa ... you're gonna take karate forever?"
-----"What? I didn't say that."

[ZhengL938]

There is a lot of overlap between Inference and Necessary Assumption, in the sense that in both cases the correct answer is an idea that was basically embedded in the meaning/logic of the paragraph.

The big difference:
Necessary Assumption questions are based on ARGUMENTS
Inference questions are based on STATEMENTS / INFORMATION / FACTS

When you read NA, you find the Conc and the supporting ideas, and you think about
1. What missing logical links/ideas are there?
2. What potential objections could be made to this argument?

When you read Inf, you're just reading facts and asking yourself, "Can I combine any of these facts to derive some Inference?"

You're way more likely to predict the eventual answer on Necessary Assumption, because the author will often have one glaring missing link separating her evidence from her conclusion.

With Inference, ANYTHING that can be derived from the facts would be a correct answer. So it's harder to pin down one specific inference that "should" be the right answer.

As for (D), the fact we are given is that
"antibodies will increase in number for the next year or so".

From that fact, can we derive the idea that
"someone infected with X will have their antibodies increase FOREVER"?

No way. We were only told that antibodies will increase for a year or so; it would be a huge leap to suddenly infer "they will increase forever".

It's basically like this:
"Bob, how much longer do you think you'll take karate classes?"
-----"For another year or so."
"Whoa ... you're gonna take karate forever?"
-----"What? I didn't say that."

Hi ohthatpatrick, I have a question with...(E)

As @giladedelman said" So if someone who has been infected by virus X for three days is tested by the new test, he won't exhibit infection because his body hasn't started producing the antibodies yet! ” But the stimulus did not equate"exhibit infection" with "producing the antibodies" So based on the statements above alone, I cannot know what "exhibiting infection" means

So is this medical knowledge suppose to be our common sence?

Thanks in advance!

[ohthatpatrick]

If Tom exhibits a weakness for high kicks, then it is apparent that Tom has a weakness for high kicks.

If Tom exhibits a fondness for chocolate, then it is apparent that Tom has a fondness for chocolate.

to exhibit = to show / to reveal

If Tom exhibits infection, then it is apparent that Tom has an infection.


They never defined what exhibiting infection would be, but common sense would tell us that "the antibody test" tests for antibodies. And the stimulus told us that antibodies are produced "after a week".

It is medical knowledge common sense that detecting antibodies for a certain condition is a way for doctors to know that you have that condition. But antibodies aren't necessarily the only way that someone could exhibit an infection / disease.

However, the way (E) is worded, it's saying "If someone is tested by the antibody test [which tries to figure out whether you're infected by testing for whether you have antibodies to a certain infection], then the antibody test would not be able to determine that a person has any antibodies [and therefore that they have the infection] for the first week of that person being infected."

(E) is saying,
"for some time [the first 6-7 days of being infected], an antibody test won't show you have the antibodies to virus X, so it won't think that you exhibit infection X"

Hope this helps.