When a stone is trimmed by a mason and exposed to the elements, a coat

Question

When a stone is trimmed by a mason and exposed to the elements, a coating of clay and other minerals, called rock varnish gradually accumulates on the freshly trimmed surface. Organic matter trapped beneath the varnish on stones of an Andean monument was found to be over 1000 years old. Since the organic matter must have grown on the stone shortly after it was trimmed, it follows that the monument was built long before the arrival of Europeans in the Americas in 1492.

Which one of the following, if true, most seriously weakens the argument?

(A) Rock varnish itself contains some organic matter.

(B) The reuse of ancient trimmed stones was common in the Andes both before and after 1492.

(C) The Andean monument bears striking resemblance to monuments found in ancient sites in western Asia.

(D) The earliest written reference to the Andean monuments dates from 1778.

(E) Rock varnish forms very slowly, if at all, on trimmed stones that stored in a dry, sheltered place.

siyer · Accepted Answer

When a stone is trimmed by a mason and exposed to the elements, a coating of clay and other minerals, called rock varnish gradually accumulates on the freshly trimmed surface. Organic matter trapped beneath the varnish on stones of an Andean monument was found to be over 1000 years old. Since the organic matter must have grown on the stone shortly after it was trimmed, it follows that the monument was built long before the arrival of Europeans in the Americas in 1492.
Which one of the following, if true, most seriously weakens the argument?

(A) Rock varnish itself contains some organic matter.
This doesn't weaken the argument.

(C) The Andean monument bears striking resemblance to monuments found in ancient sites in western Asia.
Irrelevant as no date is mentioned.

(D) The earliest written reference to the Andean monuments dates from 1778.
Irrelevant. Written references do not matter to us.

(E) Rock varnish forms very slowly, if at all, on trimmed stones that stored in a dry, sheltered place.
Doesn't help in weakening the argument.

(B) The reuse of ancient trimmed stones was common in the Andes both before and after 1492.
Correct Answer: Ancient stones were reused to build monuments in the Andes. So these stones could have been cut out off existing ancient structures and used to built the monuments. So although the stone may be old, it does not necessarily mean that the monuments were that old too.

Although I got this right, I would still call for an end to the use of spoilers. Its much better to write an explanation without knowing what the right answer is. The spoiler should be enabled after someone comes up with the right answer. Just my thoughts

whiplash2411 · Answer

As soon as you read the highlighted portion in the stimulus, your head must scream "Danger! Unfounded assumption!"

Let's look at the answer choices now:

keats · Answer

I can't still seem to understand how B

Can anyone explain in detail. Thanks in advance!

YangYichen · Answer

the premise says that the organic matter is found to be 1000 years old, so it follows that the monument is also 1000 years old
but what if the stone is reused from other architechture to build the monument shortly before 1492, but the architechture it self is 1000 years old when the stone is trimmed~
hope to be helpful~

sayantanc2k · Answer

The above explanation given by YangYichen seems sufficient. Yet I would add a bit more in case there are still some doubts:

If the organic substance found on the stone is 1000 years old, then the trimming of the stone must have been done 1000 years ago (sometime in 1000's). It is possible that something (say a statue) was constructed using the stone 1000 years ago (immediately after the stone was trimmed). Later on (in 1492) the statue may have been demolished and the stone may have been reused (option B) to construct the Andean monument. Thus the belief that the Andean monument was constructed in 1492 is still justifiable (if option B is true), and the claim that the monument was built long before 1492 is weakened.

akshaypratap278 · Answer

The argument says that the matter trapped is 1000 years old and so the monument should also be 1000 years older (that is, long before 1492)
Now let's weaken it this way:
What if we built this monument in 1493 with stones already trimmed (that is reused) 1000 years back? Yessssss, that;s the weakness

VerbalBot · Answer

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When a stone is trimmed by a mason and exposed to the elements, a coat

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When a stone is trimmed by a mason and exposed to the elements, a coat

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