By examining the fossilized leaves of any prehistoric plant

Question

By examining the fossilized leaves of any prehistoric plant, it is possible to determine the climate in which that specimen grew because the size and shape of a leaf are unique to a given climate. Since the climate at a given location depends on the altitude at that location, it follows that the size and shape of a fossilized leaf also indicates the altitude at which the plant grew.

The reasoning in the argument is vulnerable to criticism on the grounds that it

(A) fails to demonstrate that no species of plant can long survive a violent change in its environment

(B) overlooks the possibility that locations at different altitudes can have the same climate

(C) treats the size and shape of a leaf as if they were the only physical characteristics of a leaf that depend on climate

(D) relies on a weak analogy between a leaf and the fossil of a leaf as evidence for the claims advanced

(E) ignores the possibility that the location at which a fossilized leaf was found is not the location at which the original plant grew

Why can't E be an answer to this question since if E is the flaw it weakens the conclusion?

ToninoJOB · Answer

Hi, thanks for the question.

Analysing the argument, it is clear that the author wants us to believe that both size and shape of a leaf is relevant to know the climate and the altitude at which the plant grew. No looking at the answers:

A. Talks about violent change in its environment, this is out of scope
B. Locations at different altitudes can have the same climate - ok keep for the moment
C. Size and shape as the only parameters, though it is true we do not know if there are more parameters or no, so out
D. Weak analogy between leaf and fossils, this is clearly not what the passage is about, out.
E. It is reasonable to think that a leaf might end up at an altitude, and therefore, a different climate when it falls out of the tree. To me this was the most relevant flaw of the reasoning.

Can someone explain my approach and why B over E?

Thank you very much in advance

meenalkaushik · Answer

In my opinion, it is because the passage is talking about examining the fossils of a leaf of a plant and not where the fossil was found. The leaf could have flown to a different location but the plant grew in a specific location that had a specific climate

zlishz · Answer

E says that the leaf is found in a different location from where the actual plant (from where the leaf came) grew.
It might seem quite understandable but if we think about it, a person who is studying those leaves will collect the leaves from the plant rather than the leaves they find on the ground. This was my reasoning.
(Also, it seems highly unlikely that a leaf will travel all the way to a place with a different climate altogether.)

unraveled · Answer

By examining the fossilized leaves of any prehistoric plant, it is possible to determine the climate in which that specimen grew because the size and shape of a leaf are unique to a given climate. Since the climate at a given location depends on the altitude at that location, it follows that the size and shape of a fossilized leaf also indicates the altitude at which the plant grew.

The reasoning in the argument is vulnerable to criticism on the grounds that it

(A) fails to demonstrate that  no species of plant can long survive  a violent change in its environment

(B)  overlooks the possibility that locations  at different altitudes can have the same climate

(C) treats the size and shape of a leaf as if they were the  only physical characteristics of a leaf  that depend on climate

(D) relies on a  weak analogy between a leaf and the fossil of a leaf as evidence  for the claims advanced

(E) ignores the possibility that the location at which a fossilized leaf was found is  not the location at which the original plant grew

Only B and E stand to be chosen. 
E gives altogether a different direction to the passage, which is beyond the scope of the passage. It seems to suggest that Cedar(common in Himalyas) leaves fossilized but found in Rameshwaram(southern part of India). This is bit of an exaggeration. 
Whereas B straightaway touches the core aspect of the passage i.e. Climate, Location and altitude.

Answer B.

SKaur3 · Answer

Though I came up with the Right answer, I can't see strong reasons to eliminate D, as the argument states that the size and shape of a leaf can determine climate and, subsequently, Altitude.
However, it was not mentioned that leaf fossils can serve the same purpose for determining the climate, etc.
Can you help me with clearly understanding the reasoning behind eliminating 'D'

Mantrix · Answer

P1: size and shape of a leaf are unique to a given climate. 
P2: the climate at a given location depends on the altitude at that location, and 
P3: the size and shape of a fossilized leaf also indicates the altitude at which the plant grew.

C: So, By examining the fossilized leaves of any prehistoric plant, it is possible to determine the climate in which that specimen grew.

The reasoning in the argument is vulnerable to criticism on the grounds that it

(A) fails to demonstrate that no species of plant can long survive a violent change in its environment (Not Relevent)

(B) overlooks the possibility that locations at different altitudes can have the same climate (so leaf will tell us about the Shape and size, that will tell us about the altitude, but the diff altitutes also can have the same climate) so it means, it cant the clear indication of climate with the help of shape and size. (Weakener)

(C) treats the size and shape of a leaf as if they were the only physical characteristics of a leaf that depend on climate (can be other factors also, no effect)

(D) relies on a weak analogy between a leaf and the fossil of a leaf as evidence for the claims advanced (Not Relevent)

(E) ignores the possibility that the location at which a fossilized leaf was found is not the location at which the original plant grew
(if the leaf found at different location,  then also the leaf will give the climate information of weather in which plant grows , not about the climate of that place) so, No effect on the argument

DmitryFarberMPrep · Answer

This is pretty tricky, as it gets to the nature of this rare question type, the Flaw question. These are basically Assumption questions, with a bit of added complexity. The main difference is that the answers can work in more than one way: they can weaken, point out a flawed assumption, or point out a general type of bad reasoning the author uses. For the assumption answers, we sometimes see fairly neutral phrasing such as "relies on the assumption that" or "takes for granted that." However, we can also see judgier phrasing that says that the assumption in question is actually incorrect or unlikely to be true, and that's what we see in D. However, we have no basis for concluding that the assumption in question is a bad one!

If D simply pointed out that the author was assuming the fossils worked the same way as the original leaves, then sure, that would be an assumption. But D is saying that it is actively  wrong  or inappropriate to assume this, and we have no reason to say that. In real life, I'd imagine a fossilized leaf gives you a pretty strong impression of the size and shape of the original leaf. But even if I didn't know that, there's nothing in the text to suggest that the connection is weak, or that the author is really relying on an analogy. After all, we're looking at fossils of the leaves themselves. It's like looking at my X-rays: they may not give the same information as looking directly at my body, but the information they provide is not just analogous.

vasu1104 · Answer

examined fossilized leaves of prehistoric plants- possible to determine the climate they grew.
reason- size and shape of leaf are unique to given climate.
climate of location depends on altitude of that location.
conclusion- size and shapes of fossilized leaf also indicates the altitude.

there is chain structure going on here. here how it works.
climate depends - altitude.
shape and size unique to climate. figure out shape and size- figure out climate
and when figure out climate, you figure out altitude becuase climate depends on altitude.

so if we can break this chain, we can break the conclusion and hence weaken it.
may be they are assuming that every climate is unique baes on its altitude and no chance of overlapping with different altitude.

A this somehow reinforce the belief back in conclusion. reject.
B if different altitude can have same climate then its going to bad idea to rely on fact that determining climate can help you determining altitude. so this clearly attacks the conclusion and provide the weak link missing in arguments, perfect.
C but say there are other similar characteristics but who cares. if the leaves can get to the ans we are still good with conclusion. reject.
D irrelevant. here clearly focused on fossilized leaf. out.
E yeah and thats what argument is trying to establish. so regardless of where they were found but as long as we examine their size and shape, we can trace back their original root. reject.

sashankmvv1234 · Answer

" Since the climate at a given location depends on the altitude at that location," this is the premise, right? If we go with option B, aren't we attacking the premise? Premise says that climate depends on altitude. But if we say that two different altitudes have same climate, are we indirectly saying that climate does not depend on altitude?

GMATNinja

GMATNinja

AbhishekP220108 · Answer

Hi  sashankmvv1234  let me try to help

Lets check the structure of the argument

Examine the FL of PL-shape and size-unique to a climate
(Ex-Long and thrones leave-humid climate)

Climate depends on altitude

Conclusion- size and shape-use to determine altitude where plant grew

So basically author is assuming 
Examine the FL of PL-shape and size-unique to a climate-so altitude is determined.

But from argument we only know Climate depends on altitude, it may be possible that the within 100km there is humid climate at 700 mtr and 1000 mtr

Option (B) is trying to say the exact thing that if we consider the possibility that locations at different altitudes can have the same climate, then how can we determine the the unique altitude.

Hope this helps

guddo · Answer

By examining the fossilized leaves of any prehistoric plant, it is possible to determine the climate in which that specimen grew because the size and shape of a leaf are unique to a given climate. Since the climate at a given location depends on the altitude at that location, it follows that the size and shape of a fossilized leaf also indicates the altitude at which the plant grew.
 
 The reasoning in the argument is vulnerable to criticism on the grounds that it

The argument says leaf size and shape identify climate, and climate depends on altitude. Then it concludes that leaf size and shape identify altitude.  The flaw is that the relationship may not be one-to-one : the same climate could occur at different altitudes in different places.

(A) fails to demonstrate that no species of plant can long survive a violent change in its environment

Wrong. The argument is about using fossilized leaves to infer climate and altitude, not about whether plants can survive environmental changes.

(B) overlooks the possibility that locations at different altitudes can have the same climate

Correct. Even if altitude affects climate, it does not follow that each climate corresponds to only one altitude. If different altitudes can share the same climate, then the leaf can indicate the climate but not necessarily the  altitude .

(C) treats the size and shape of a leaf as if they were the only physical characteristics of a leaf that depend on climate

Wrong. The argument does not need size and shape to be the only climate-related characteristics. It only claims they can indicate climate.

(D) relies on a weak analogy between a leaf and the fossil of a leaf as evidence for the claims advanced

Wrong. The argument is not based on an analogy between a living leaf and a fossilized leaf.

(E) ignores the possibility that the location at which a fossilized leaf was found is not the location at which the original plant grew

Wrong. The conclusion is about the altitude at which the plant grew, not necessarily the altitude where the fossil was found.

Answer: (B)

sashankmvv1234 · Answer

But my query is that how can two different altitudes have different climate as mentioned in the options. Clearly author has mentioned that with the use of since "climate depends on altitude". While we take options as true, this option looks more like attacking the premise rather than conclusion.

KarishmaB can you help please?

KarishmaB  can you help please?

KarishmaB · Answer

We are given:  Since the climate at a given location depends on the altitude at that location...
Climate depends on altitude but that doesn't mean it depends only on altitude. In fact we know that it depends on latitude too. Climate near the equator is very different from climate near the poles even if the altitude (height from sea level) is the same. So it is a flaw in the argument that it fails to take into consideration that climate could be dependent on other factors too. So locations at different altitudes can have the same climate and locations as same altitude can have different climate but the argument fails to consider this.

Nav_124 · Answer

This is a classic “correlation / mapping” flaw.

The argument assumes a one-to-one relationship:

Climate → unique altitude

But only tells us:

Altitude influences climate

That is not enough to reverse the relationship.

Think of it like:
"Fever can be caused by flu.
Therefore, anyone with fever has flu."

Wrong because multiple causes can produce the same effect.

So the answer is (B).

sashankmvv1234 · Answer

Thanks a lot for your explaination. So we can attack the premise of the argument? Pls correct me if i am wrong..

KarishmaB · Answer

No. A depends on B does not mean that A depends on B only. There could be other factors too on which A could depend. 
The premise only tells us that A depends on B. The flaw is that the author ignored the possibility that A depends on other factors too.

By examining the fossilized leaves of any prehistoric plant

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By examining the fossilized leaves of any prehistoric plant

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