#8 - Measurements of the extent of amino-acid decomposition

[Administrator]

Complete Question Explanation

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

This fact-based stimulus describes how eggshell fragments can be used for dating archeological sites. In warmer climates where amino-acid decomposition is faster, the method can only be used to obtain accurate dates for sites up to 200,000 years old. Cooler climates slow decomposition and the technique can be useful for sites almost a million years old. Clearly, then, the climate of a particular region determines the extent to which the eggshell technique can be used to date the archeological site found in that region.

Answer choice (A): Cooler regions allow for the eggshell technique to be used on older sites. This does not, of course, mean that the oldest sites are found in cooler regions.

Answer choice (B): It is entirely possible that the amino-acid decomposition is found in other organic matter. The author never said that eggshells are the only organic matter susceptible to this approach.

Answer choice (C): This is the correct answer choice. If the climate of a particular region determines the extent to which the eggshell technique can be used to date the archeological site found in that region, and the site being dated had been subject to large unsuspected climatic fluctuations, then the rate of amino-acid decomposition may have been subject to erratic fluctuations that scientists cannot account for. Notice the language used to express likelihood: application of the technique is less likely to yield accurate results. Proving that a certain outcome is less likely to occur is a lot easier than proving that this outcome will never occur. Extreme language is rarely the hallmark of a good Must Be True answer.

Answer choice (D): If cooler climates allow for the dating of sites almost a million years old, it is unclear why after 200,000 years the technique will no longer be suitable for use. This answer choice is disproven by the stimulus and is incorrect.

Answer choice (E): If a warmer climate enable faster decomposition of amino-acids, we may be more likely to find eggshell fragments at sites in cooler regions, not in warmer ones. Even if no inference can be made about the relative likelihood of finding eggshell fragments in warmer versus colder regions, this answer choice is incorrect.

[reop6780]

Hi, are there people studying question type training?

On page 24, number 14 of must be true section, the answer key is stated to be C.

The problem I have with this answer is due to the word, "unsuspected." Instead of climatic fluctuations, the answer chooses to say unsuspected climatic fluctuations. For that matter, I canceled the answer. However, it turned out to be the right one.

Can anyone explain why the word unsuspected does not make the change?

[Dave Killoran]

Hi Reop,

Thanks for the question! If the number of copies sold is any indication, then a lot of people are studying them

Let's take a look at the question you ask about, where (C) is indeed the correct answer. First, let's note that (C) is presented in the form of a conditional, so the "unsuspected" element is being added in (this is ok as long as the form is conditional). Second, let's look at what the stimulus says about the use of the dating technique: "Because the decomposition is slower in cool climates, the technique can be used to obtain accurate dates for sites almost a million years old in cooler regions." So, in the stimulus, they are talking about a dating technique based on decomposition, and in cooler areas the decomposition is slower, allowing for a accurate dating up to a million years. But, what if, unbeknownst to the researchers, there had been large climatic variations (meaning things got warm sometimes)? How would that affect the dating process? You are probably thinking it would make it less reliable, and you'd be correct. This is then what the remainder of answer choice (C) states.

Thus, if there had been unsuspected variations, the results would not be as reliable. Answer choice (C) must be true, then, and is the correct answer.

Please let me know if that helps. Thanks!

[reop6780]

[quote="Dave Killoran"}

Hi, Dave!

Thank you so much, and it helped me a lot.

I assumed the insertion of word "unsuspected" in such context would reverse the meaning of climatic fluctuations in that researchers would predict the dates based upon the unsuspected climate. However, the role of "unsuspected" is not meant to be strong enough to change the context, I see.

I was wondering whether "unsuspected" was necessary to be used in conditional sentence.

Thank you, and I feel more relived to ask more questions while studying !

Hyun Kim

[Dave Killoran]

Hi Hyun,

Glad I could help!

Are you asking if "unsuspected" could be used in that question validly, without having it appear in a conditional format? It's pretty unlikely that they could or would do that, I think.

Please let me know if that helps. Thanks!

[reop6780]

Sorry to bother you with the same question over and over.

I read "must be true" chapter again in LR bible, but still did not understand why "unsuspected" is more likely to be used in a conditional statement.

Is it necessary to use "unsuspected" when it comes to the conditional form in this case?

Or, does the conditional form allow the use of "unsuspected"?
( in that it is less likely to be used in non-conditional statement)

If it were not written in conditional form, the use of "unsuspected" could cancel out the answer, right?

Thank you

Hyun Kim

[Dave Killoran]

Hi Hyun,

Thanks for the reply. Let's try to break it down:

Did the test makers have to have a correct answer with "unsuspected" in it? No, they didn't. They could have made an answer that never used unsuspected, and went in a different direction entirely.

Could they have used "unsuspected" in a correct answer choice for this problem that wasn't in conditional form? Not likely. There's nothing in the stimulus suggesting there were unsuspected climate fluctuations. Thus, such a statement would not have been supported outright by the stimulus.

Is the use of the conditional form what allows "unsuspected" to work in this correct answer? Yes, because the conditional form allows the test makers to add in a new consideration, and then draw a conclusion. This is what (C) does.

Please let me know if that helps. Thanks!

[reop6780]

Thank you so much !

[Blueballoon5%]

(Question removed for copyright reasons)

My question: I don't understand why choice A is wrong. The answer book explains that we can infer choice C as the correct answer. However, couldn't we also infer that choice A is correct as well? In south Africa, the archaeological sites can go back as far as 200,000 years. In cooler places, the sites can go back even longer. Wouldn't that allow us to infer that the oldest archaeological sites are in cooler areas and not in south Africa?

[Adam Tyson]

The stimulus tells us that we can use the technique to determine dates for the sites, and that in colder climates we can use it to look back farther than at warmer sites. The focus is on how long the technique works - 200,000 years vs. nearly a million years - but that tells us nothing about how old the sites actually are. Couldn't we find a 10 million year old site in Africa, and just be unable to use this technique to date it? African sites could be much, much older than any found in colder regions, and perhaps we could use some other technique to date them, or perhaps we can't date them at all. All we know is that in the warm places, the egg method will only allow us to look back so far. Just because the technique gives us more far-ranging data in the cold places doesn't mean the cold places are older.

I hope that cleared things up!