Measurements of the extent of amino-acid decomposition in fragments of

Question

Measurements of the extent of amino-acid decomposition in fragments of eggshell found at archaeological sites in such places as southern Africa can be used to obtain accurate dates for sites up to 200,000 years old. 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.

The information above provides the most support for which one of the following conclusions?

(A) The oldest archaeological sites are not in southern Africa, but rather in cooler regions of the world.

(B) The amino-acid decomposition that enables eggshells to be used in dating does not take place in other organic matter found at ancient archaeological sites.

(C) If the site being dated had been subject to large unsuspected climatic fluctuations during the time the eggshell has been at the site, application of the technique is less likely to yield accurate results.

(D) After 200,000 years in a cool climate, less than one-fifth of the amino acids in a fragment of eggshell that would provide material for dating with the technique will have decomposed and will thus no longer be suitable for examination by the technique.

(E) Fragments of eggshell are more likely to be found at ancient archaeological sites in warm regions of the world than at such sites in cooler regions.

Bunuel · Accepted Answer

OFFICIAL EXPLANATION

This is another straightforward, fact-based question. Since the accuracy of the technique depends on temperature, any prolonged change in climate will affect its accuracy. For example, if a particular site now has a cool climate but for most of its past had a tropical climate, then the results from applying the technique would be misleading.  The answer is (C).

The other choices are easily dismissed. Choice (A) is not supported by the passage. Climate affects the accuracy of the dating technique, not the age of the site itself. Choice (B) is perhaps second best. Although it is reasonable to assume that some characteristic of eggshells makes them preferable to other organic materials, nothing in the passage implies that the type of amino-acid decomposition found in eggshells is unique. Choice (D) is not supported by the passage. Nothing in the passage indicates the amount of amino acid needed in the eggshell for the technique to be accurate. Finally, choice (E) is not supported by the passage. The passage discusses only the accuracy of the amino-acid method of dating; it does not discuss or imply that fragments of eggshell are more likely to be found in some areas than in others.

thouhid · Answer

The question asks us to identify a conclusion for which the statements offer the most support. We know the following:

1. a technique measuring amino-acid decomposition can be used to date archeological sites in place like South Africa as far back as 200,000 years.
2. because amino-acid decomposition is slower in cooler climates, this technique can be used to date archeological sites in cool climates as far back as one million years.

Answer choice (C) is supported because the technique relies on the rate of decomposition of amino-acids which are affected by climatic conditions. If the climatic conditions have fluctuated and can not be taken into account, then the rate of decomposition would vary during the climatic fluctuations and so cannot be accounted for during the analysis.

Incorrect Answers
(A) is unsupported. The statements do not suggest where the oldest archeological sites are located. It only discusses the effectiveness of using this technique based on climatic conditions.
(B) is unsupported. We know that this technique is used by measuring amino-acid decomposition in eggshells, but the statements do not suggest that this amino-acid decomposition only occurs in eggshells.
(D) is contradicted by the statements. We know that this technique is suitable in cooler climates for dating archeological sites as far back as one million years.
(E) is unsupported. The statements do not suggest where eggshells are more likely to be found.

AnirudhaS · Answer

Bumping up for further discussions.
I am not convinced why D is incorrect. 
1/5th of the egg shell would have decomposed and not used for examination, but the rest 4/5th portion can be. What am I missing here?

GMATTER18 · Answer

Conclusion: the technique can be used to obtain accurate dates for sites almost a million years old in cooler regions.

What we need to strengthen is this conclusion that the Technique will work in Cool climate and can be used to accurately dates sites for almost a million years.

As per argument why technique will work : As the rate of decomposition is slower( Given in argument ) and is constant( Assumed ) in cool climate .

So if the rate is constant then the technique will work if not then the technique will fail.

Option C says: If the rate is not constant then Technique might fail for both cool and hot climate (Correct)

Option D says: From the argument, we have already established that technique will work on 200,000 years sire estimation but D says Even if climatic conditions are constant still less than 1/5th of the decomposition will happen means expected decomposition is more . Hence this option says 200,000 years estimation can't be done using this technique and contradicts the premise .

GowriPrakash · Answer

The conclusion talks about obtaining accurate dates for sites almost 1,000,000 (million) years old in cooler regions.

If after 200,000 the eggshell has decomposed 1/5th and cannot be used for examination, it might decompose completely before a million years old.

I hope I have answered your question.

TarPhi · Answer

Hello! It's not stated that the decomposition is happening in Arithmetic progression. It could be happening in GP. Answer C is much better because it says that once it's been in one climate type, it can't be tested for another eg if temperature fluctuated or if someone moved the eggshell after 100,000 years, it might not have only decomposed 1/10th. Please Kudos if this helped!

And good luck for your GMAT!

HRX273 · Answer

hey, can anyone help me out with why not a ??

Sajjad1994 · Answer

Hi

The question is explained  here

Measurements of the extent of amino-acid decomposition in fragments of

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