Last visit was: 01 May 2026, 10:03

It is currently 01 May 2026, 10:03

Toolkit

Practice Tests

Critical Reasoning (CR)

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Go to My Error Log Learn more

Request Expert Reply

Confirm Cancel

Back to Forum

Create Topic

12 Days of Christmas GMAT Competition 2025 - Day 7: In analyzing the

1 2 3 4

geocircle

Joined: 14 Dec 2025

Last visit: 27 Dec 2025

Posts: 90

Own Kudos:

Posts: 90

Kudos: 87

24 Dec 2025, 08:07

Kudos

Bookmarks

A It introduces a "potential" disadvantage. It does not show that these species survive less long overall nor that the fossil trend is mistaken.

B Global extinction events are not localized disturbances.

C It suggests localized species can be resilient, but this does not explain why the fossil record shows broader-range species surviving longer.

D Right answer. It directly attacks the foundation of the argument, the fossil record evidence.

E Anecdotal counterexamples do not refute a general trend.

Answer D

gemministorm

Joined: 26 May 2025

Last visit: 29 Apr 2026

Posts: 143

Own Kudos:

112

[1]

Given Kudos: 57

GMAT Focus 1: 565 Q82 V79 DI73 Verified score

GMAT Focus 2: 605 Q84 V83 DI73 Verified score

Products:

GMAT Focus 2: 605 Q84 V83 DI73 Verified score

Posts: 143

Kudos: 112

[1]

24 Dec 2025, 08:11

Kudos

Bookmarks

Argument -> species with broader ranges are more likely to persist over evolutionary timescale.
We need to weaken->
A and B -> close call
A -> more vulnerable to extinction but if they get extinct or not we do not know.
B -> evidence showing species with broad habitat range went extinct compared to less broad habitat range.
C, D, E -> weaken but not for surety - it's like could be(will require more assumptions) and we want a must be weakener.

hence B.

bhanu29

Joined: 02 Oct 2024

Last visit: 30 Apr 2026

Posts: 363

Own Kudos:

276

Given Kudos: 263

Location: India

Schools: Anderson '27 Booth '27 Foster '27 Haas '27 Kellogg '27 Kellogg Mashall '27 McCombs '27 Ross '27 Scheller '27 Tepper '27 Yale '27 Sloan (MIT) Stanford '27

GMAT Focus 1: 675 Q87 V85 DI79 Verified score

GMAT Focus 2: 715 Q87 V84 DI86 Verified score

GPA: 9.11

WE:Engineering (Technology)

Products:

Schools: Anderson '27 Booth '27 Foster '27 Haas '27 Kellogg '27 Kellogg Mashall '27 McCombs '27 Ross '27 Scheller '27 Tepper '27 Yale '27 Sloan (MIT) Stanford '27

GMAT Focus 2: 715 Q87 V84 DI86 Verified score

Posts: 363

Kudos: 276

24 Dec 2025, 08:19

Kudos

Bookmarks

Bunuel

In analyzing the fossil record, paleontologists have found that species with broader geographic ranges tend to survive longer than those with more localized habitats. One explanation is that widespread species are more resilient to localized environmental disturbances, such as droughts or disease outbreaks. Consequently, researchers argue that species with larger habitat ranges are more likely to persist over evolutionary timescales than those with limited distribution.

Which of the following, if true, most seriously undermines the reasoning in the argument above?

A. Species with broad geographic ranges often experience high levels of genetic divergence across subpopulations, making them more vulnerable to speciation and eventual extinction.
B. Several species that went extinct during past global extinction events had significantly larger habitat ranges than many surviving species.
C. Localized species are often better adapted to niche ecosystems and may evolve specialized traits that increase their chances of surviving specific environmental changes.
D. Fossil evidence is incomplete and may overrepresent species with larger ranges, which are more likely to leave behind fossil traces across regions.
E. Some species with limited geographic ranges have persisted for tens of millions of years without significant change.

Gift

12 Days of Christmas Competition

This question is part of our holiday event

Win $40,000 in prizes: courses, tests, and more

Weaken question:
A. Species with broad geographic ranges often experience high levels of genetic divergence across subpopulations, making them more vulnerable to speciation and eventual extinction.
Slightly weakens but this only gives us a reason to doubt the conclusion, Keep if better answer not found this might be answer.
B. Several species that went extinct during past global extinction events had significantly larger habitat ranges than many surviving species.
Some patterns doesn't mean universal. Eliminate.
C. Localized species are often better adapted to niche ecosystems and may evolve specialized traits that increase their chances of surviving specific environmental changes.
Even if this is true, conclusion still can hold, species with long ranges still might survive. Eliminate.
D. Fossil evidence is incomplete and may overrepresent species with larger ranges, which are more likely to leave behind fossil traces across regions.
This directly shows there is a flaw in the premise, if the evidence itself is flawed, then the entire argument falls apart, better than choice A. Keep.
E. Some species with limited geographic ranges have persisted for tens of millions of years without significant change.
Fact about some species cannot be generalized. Eliminate.
Correct Answer: D

topgmat25

Joined: 15 Dec 2025

Last visit: 05 Jan 2026

Posts: 90

Own Kudos:

Posts: 90

Kudos: 87

24 Dec 2025, 08:23

Kudos

Bookmarks

A This doesn't directly address the observed correlation, it just says "they might be more vulnerable".

B The argument is about resilience to localized disturbances, not global catastrophes.

C It's speculative ("may evolve"), and doesn't directly address the fossil record correlation.

D If the correlation is an artifact of preservation prejudice, the whole argument collapses. Correct answer.

E This is just an exception, not undermining the general argument.

The answer is D

prepapr

Joined: 06 Jan 2025

Last visit: 29 Apr 2026

Posts: 92

Own Kudos:

Given Kudos: 6

GMAT Focus 1: 615 Q85 V80 DI77 Verified score

Products:

GMAT Focus 1: 615 Q85 V80 DI77 Verified score

Posts: 92

Kudos: 82

24 Dec 2025, 08:32

Kudos

Bookmarks

Context: aleontologists observe that the species with broader geographic ranges tend to survive longer than species with localised habitats
Conclusion: Species with larger habitats are more likely to persist over revolutionary timescales than species with limited habitats
Logical gap: Argument assumes that the fossil record represents the true survival patterns

Evaluating options:
A)Introduces a disadvantage for wide range species but this does not challenge the conclusion
B) Focusses on global extinction events which might be a special case
C) Suggests localised species can adapt well. This does not challenge conclusion
D) This attacks the reliability of the evidence. this directly attacks the conclusion. Species with larger geographic ranges are more likely to leave fossils simply because they exist in more places.
E) This is an exeption. This does not challenge the conclusion

Hence D is the answer

Bunuel

Gift

12 Days of Christmas Competition

This question is part of our holiday event

Win $40,000 in prizes: courses, tests, and more

sanjitscorps18

Joined: 26 Jan 2019

Last visit: 03 Mar 2026

Posts: 723

Own Kudos:

743

Given Kudos: 130

Location: India

Schools: IMD'26

Products:

Schools: IMD'26

Posts: 723

Kudos: 743

24 Dec 2025, 08:39

Kudos

Bookmarks

A -> This suggests that diversification makes them vulnerable, but the argument can still hold against comparison with species with limited distribution
B -> Several suggests that some of them also survived hence this may not be strong enough
C -> This talks about adaptation of local species but this may still coexist with the data provided
D -> Correct. If the fossil records are not representative, then the whole theory falls apart. The basis of the observations doesn't stand because the different between fossil records may not exist at all.
E -> This may be true, but it doesn't provide a reference point of timelines.

Option D

Bunuel

Gift

12 Days of Christmas Competition

This question is part of our holiday event

Win $40,000 in prizes: courses, tests, and more

firefox300

Joined: 15 Dec 2025

Last visit: 27 Dec 2025

Posts: 90

Own Kudos:

Posts: 90

Kudos: 87

24 Dec 2025, 08:40

Kudos

Bookmarks

A This contradicts the fossil record finding. So either fossil record is wrong or this effect isn't strong enough to change the tendency.

B Irrelevant. The argument is about local disturbances, not global disasters.

C This just says "sometimes small-range species are tough too", but it doesn't challenge why the fossil record shows the opposite trend.

D CORRECT. This directly destroys the starting fact. If fossil evidence is incomplete, the argument falls apart.

E The argument doesn't say all small-range species die quickly.

The correct answer is D

Reon

Joined: 16 Sep 2025

Last visit: 29 Apr 2026

Posts: 134

Own Kudos:

121

[1]

Given Kudos: 4

Posts: 134

Kudos: 121

[1]

24 Dec 2025, 08:43

Kudos

Bookmarks

In analyzing the fossil record, paleontologists have found that species with broader geographic ranges tend to survive longer than those with more localized habitats. One explanation is that widespread species are more resilient to localized environmental disturbances, such as droughts or disease outbreaks. Conclusion: species with larger habitat ranges are more likely to persist over evolutionary timescales than those with limited distribution.

Which of the following, if true, most seriously undermines the reasoning in the argument above?

A. Species with broad geographic ranges often experience high levels of genetic divergence across subpopulations, making them more vulnerable to speciation and eventual extinction. (This only suggest a possibility, that high level of genetic divergence makes them more vulnerable) Wrong

B. Several species that went extinct during past global extinction events had significantly larger habitat ranges than many surviving species. (This option says that the wide range did not protect the species during global extinction events. This directly weakens the ideas that resilience to localised disturbances guarantee long term survival) Correct

C. Localized species are often better adapted to niche ecosystems and may evolve specialized traits that increase their chances of surviving specific environmental changes. (This option doesn't weaken the main conclusion) Wrong
D. Fossil evidence is incomplete and may overrepresent species with larger ranges, which are more likely to leave behind fossil traces across regions. (The argument doesn't fully depend on the fossil data and it only questions the data and not the main conclusion) Wrong

E. Some species with limited geographic ranges have persisted for tens of millions of years without significant change. (Some is not a weakener) Wrong

Mardee

Joined: 22 Nov 2022

Last visit: 02 Feb 2026

Posts: 225

Own Kudos:

191

Given Kudos: 20

Posts: 225

Kudos: 191

24 Dec 2025, 08:54

Kudos

Bookmarks

A. Not as relevant since it doesent exactly show that the unconclusion is not reliable as both effects could coexist
B. Irrelevant as exceptions cannot be used for general trends and it doesent seriously undermine here
C. Irrelevant as it talks about localized species but doesent explain the widespread ones. It also doesent explain the fossil trends
D. Relevant as it directly attacks the evidence since if wideranging species are more likely to be preserved and found then they will look like they have survived longer even if they didnt, which would undermine reasoning from the fossils to survival theory conclusions
E. Irrelevant as this again gives us exceptions and not about general trend by using "some". This doesent seriously undermine

D

sunshineeee

Joined: 17 May 2020

Last visit: 09 Apr 2026

Posts: 96

Own Kudos:

[1]

Given Kudos: 223

Location: Indonesia

Schools: Stern '26 (WL) Tepper '26 (WL) BU'26 (A) Ross '26 Johnson '26

Posts: 96

Kudos: 22

[1]

24 Dec 2025, 09:00

Kudos

Bookmarks

The question is asked about WEAKENING.
Simplify it

Conclusion: LBR (Larger Habitat Ranges) >> LD (Limited Distribution in terms of persistence over EVOLUTINARY TIMESCALES

Why?
- LDR survive longer than LDs
- LD (= widespread species ) are more resilient to localized environmental disturbances

Assumption:
persist in evolutinatry timesscales = persist localized environmental disturbance

Weaken -> evolutiary time scales share different impact with persist in localized environmental disturbance

So, B. is answer because show Larger Habitat Ranges went extinct despite reason disturbance

Why are others incorrect?

A. genetics
C. strengthen
D. irrelevant. fossil evidence
E. strengthen.

Bunuel

Gift

12 Days of Christmas Competition

This question is part of our holiday event

Win $40,000 in prizes: courses, tests, and more

redandme21

Joined: 14 Dec 2025

Last visit: 05 Jan 2026

Posts: 97

Own Kudos:

Posts: 97

Kudos: 87

24 Dec 2025, 10:27

Kudos

Bookmarks

bb, hr1212 "localized environmental disturbances" ia the same as "global extinction events"?. They look quite different...

hr1212

GMAT Forum Director

Joined: 18 Apr 2019

Last visit: 01 May 2026

Posts: 938

Own Kudos:

1,362

Given Kudos: 2,218

GMAT Focus 1: 775 Q90 V85 DI90 Verified score

Products:

Expert

Expert reply

GMAT Focus 1: 775 Q90 V85 DI90 Verified score

Posts: 938

Kudos: 1,362

25 Dec 2025, 10:24

Kudos

Bookmarks

Hi redandme21,

While “localized environmental disturbances” and “global extinction events” are clearly different, that difference is exactly where the argument falls apart. The explanation only shows that having a broad geographic range might help a species deal with local problems like regional droughts or disease outbreaks. But the conclusion stretches much further, claiming that larger habitat ranges improve survival over evolutionary timescales, even though such timescales might be shaped not only by localized disturbances but also by global extinction events. Choice B challenges this jump by pointing out that many species with wide geographic ranges still went extinct during global events, while some narrowly distributed species survived. This shows that being resilient to localized disturbances does not automatically translate into long-term evolutionary survival.

redandme21

bb, hr1212 "localized environmental disturbances" ia the same as "global extinction events"?. They look quite different...

mkeshri185

Joined: 01 May 2025

Last visit: 22 Apr 2026

Posts: 110

Own Kudos:

Given Kudos: 2

Posts: 110

Kudos: 8

25 Dec 2025, 12:54

Kudos

Bookmarks

bb
hr1212

Consequently, researchers argue that species with larger habitat ranges are more likely to persist over evolutionary timescales than those with limited distribution.

This is the conclusion of passage. It says 'MORE LIKELY' means the chances are very high say 80-90%. But it never says they will 'DEFINITELY' survive more. And option B says 'SEVERAL' of the past species were not able to survive even after having large range. But it is definitely be possible. Lets say out of 100 species 15 species were not able to survive even after having large range. so what? It doesn't weak or undermine the argument. There are still 85 species who survived. We can't say about what proportion of the species survived. If the option were something like this 'MOST' of the species were not able to survive then we can surely say that large scale is not helping in surviving.

In short i just wanna say that question only says 'MORE LIKELY' which is NOT EQUAL TO 'MOST LIKELY'/'DEFINITELY'/'SURELY'
And option B just says 'SEVERAL' which is NOT EQUAL TO 'ALL'/"MOST'. So i dont think B is really weaking the argument.

Bunuel

GMAT Club Official Explanation:

A. Says widespread species have more genetic divergence, which could make them more vulnerable to speciation and extinction. Speciation doesn't necessarily mean extinction, and it doesn’t challenge the claim that larger ranges help species survive longer.

B. Says some species with large ranges still went extinct while others with smaller ranges survived. This contradicts the idea that having a large range increases survival chances. It’s a clear counterexample. This seriously weakens the argument.

C. Says species with small ranges might be better adapted to specific environments. That might help in some cases, but it doesn’t prove that large ranges are not helpful. It adds an alternative point, but it’s not strong enough to seriously damage the original reasoning.

D. Says fossil data might be biased toward species with larger ranges since they leave more fossil traces. This challenges the reliability of the data behind the argument. It weakens the argument by questioning the evidence, but not the reasoning itself.

E. Says some small-range species have lived a long time. This shows exceptions, but one or two examples don’t break a general trend. It’s too weak to seriously undermine the logic.

egmat

e-GMAT Representative

Joined: 02 Nov 2011

Last visit: 27 Apr 2026

Posts: 5,632

Own Kudos:

33,441

Given Kudos: 707

GMAT Date: 08-19-2020

Expert

Expert reply

Posts: 5,632

Kudos: 33,441

25 Dec 2025, 23:42

Kudos

Bookmarks

The Argument: Big range = better survival chances

Your Concern: B only says "several" large-range species died. That's not enough to hurt "more likely."

The Problem:
You missed the comparison in B.
B doesn't just say large-range species died.
B says large-range species died while smaller-range species in the same event survived.
That's not an exception. That's a reversal.

Simple Analogy:

Argument: "Umbrellas keep you drier in rain"
Weak attack: "Some people with umbrellas got wet" ← You thought B was this
Strong attack: "In several storms, people WITH umbrellas got wetter than people WITHOUT" ← This is what B actually says

When the group that's supposed to do better actually does worse, that weakens the argument - regardless of whether it says "several" or "most."

mkeshri185

redandme21

Joined: 14 Dec 2025

Last visit: 05 Jan 2026

Posts: 97

Own Kudos:

Posts: 97

Kudos: 87

28 Dec 2025, 07:18

Kudos

Bookmarks

bb
hr1212
mkeshri185

egmat, your reasoning has a flaw.
When you say, in the strong attack: "In several storms...", you should say: "In flood myth (equivalent to global extinction event)...". And you should take into account the probability that flood myth occurs.

Let's do it with maths, using conditional probability, so Bunuel can participate.

I have found in Google that:

p(global extinction event occurs) = 0.15, so p(global extinction event doesn't occur) = 1-0.15 = 0.85

So:
p(persist over evolutionary timescales) =
p(persist over evolutionary timescales|global extinction event occurs)*p(global extinction event occurs) + p(persist over evolutionary timescales|global extinction event doesn't occur)*p(global extinction event doesn't occur)

p(persist over evolutionary timescales) = 0.15*p(persist over evolutionary timescales|global extinction event occurs) + 0.85*p(persist over evolutionary timescales|global extinction event doesn't occur)

As it is said in the passage, p(persist over evolutionary timescales|global extinction event doesn't occur) for widespread species is greater than for non-widespread species, for example:

widespread species: 0.7
non-widespread species: 0.5

And, as it is said in B, p(persist over evolutionary timescales|global extinction event occurs) for non-widespread species is greater than for widespread species, for example:

widespread species: 0.1
non-widespread species: 0.9

Calculating probabilities:

widespread species:
p(persist over evolutionary timescales) = 0.15*0.1 + 0.85*0.7 = 0.015 + 0.595 = 0.61

non-widespread species:
p(persist over evolutionary timescales) = 0.15*0.9 + 0.85*0.5 = 0.135 + 0.425 = 0.56

As you see, probability of persist over evolutionary timescales is greater for widespread species than for non-widespread species even if, in global extinction events, their probabilities differ greatly (0.1 vs 0.9).
Why?, because the probability that a global extinction event occurs is much smaller than that it doesn't occur (0.15 vs 0.85).

And that's why B is not correct and the answer should be D.

egmat

Argument: "Umbrellas keep you drier in rain"
Weak attack: "Some people with umbrellas got wet" ← You thought B was this
Strong attack: "In several storms, people WITH umbrellas got wetter than people WITHOUT" ← This is what B actually says

When the group that's supposed to do better actually does worse, that weakens the argument - regardless of whether it says "several" or "most."

egmat

e-GMAT Representative

Joined: 02 Nov 2011

Last visit: 27 Apr 2026

Posts: 5,632

Own Kudos:

33,441

Given Kudos: 707

GMAT Date: 08-19-2020

Expert

Expert reply

Posts: 5,632

Kudos: 33,441

29 Dec 2025, 01:55

Kudos

Bookmarks

mkeshri185 - Let's look at the exact logic, no outside information needed.

The Argument's Claim:
"Large range species are more likely to persist than small range species"

This is a comparative claim: Large > Small

What B Actually Shows:

| Who DIED? | Who SURVIVED? |
|-----------|---------------|
| Large-range species | Small-range species |

In global events: Small > Large

That's a direct reversal of the comparative relationship.

The Fatal Gap:

The argument claims large range wins "over evolutionary timescales."

Evolutionary timescales include BOTH local AND global events.

But the argument only proved large range wins in local events.

B shows: In global events, the relationship reverses.

Simple Example:

"Large corporations handle daily operational challenges better because they have more resources and specialized departments. Therefore, large corporations are more likely to survive long-term than small businesses."

Weakener: "In several economic recessions, small businesses survived while many large corporations went bankrupt."

Does it matter that recessions are "rare"? No.

The argument claimed large corporations win long-term, but only proved they win during normal times. The weakener shows they lose during recessions - a reversal in a scenario the argument ignored.

You cannot claim "X wins overall" when:
- You only proved X wins in Scenario A
- There's evidence X loses in Scenario B

Why your probability argument doesn't apply:

You're trying to defend the conclusion by speculating that global events are rare. But:
1. The passage gives us zero information about frequency
2. CR doesn't require disproving - just creating doubt
3. B provides actual historical evidence of reversal

---

Why D is Wrong:

D says fossil evidence "may overrepresent" large-range species.

Two fatal problems:

Problem 1:"May" = speculation, not evidence

D doesn't say the data IS biased. It says it MIGHT be biased. That's a possibility, not a fact.

D creates uncertainty about the data. B provides direct evidence against the conclusion.

Same example:

"Large corporations are more likely to survive long-term than small businesses."

D-style attack: "Business survival records may be incomplete and might overrepresent large corporations."
→ Okay, so maybe we don't have perfect data. But large corporations could still survive longer - we just aren't sure.

B-style attack: "In several recessions, small businesses survived while large corporations went bankrupt."
→ We now have actual evidence that large corporations don't always survive better. The conclusion is directly challenged.

| D | B |
|---|---|
| "Maybe your evidence is flawed" | "Here's proof your conclusion failed" |
| Conclusion could still be true | Conclusion is directly contradicted |

---

Answer: B

redandme21

redandme21

Joined: 14 Dec 2025

Last visit: 05 Jan 2026

Posts: 97

Own Kudos:

Posts: 97

Kudos: 87

30 Dec 2025, 08:46

Kudos

Bookmarks

Again, your analogy is incorrect. Recessions are far far more common compared to normal times than global extinction events are compared to localized environmental disturbances.

In fact, in my explanation with numbers, I said that the probability of a global extinction event was 15% according to Google. But that's for the future. Because now there's nuclear weapons... that could make it happen. In the past, which is what the passage refers to, that probability was much lower. It was negligible. There have only been 5 global extinctions events in world history. And it is estimated that over 80% of all extinctions occur during these intervening periods. This means that most extinctions happen between global extinction event, albeit at a slower and less noticeable rate.

It's true that the reader of the passage doesn't necessarily know that, but "global extinction event" sounds so so extreme compared to "localized environmental disturbances" that for that reason alone, that option should be discarded.

"May" is speculation, yes. But this "may" undermines the reasoning much more than option B. And, as "in the land of the blind, the one-eyed man is king", D must be preferred to B.

bb, hr1212, Bunuel, just to clarify, you're not going to change the correct answer to D and assign points accordingly, are you?

egmat

hr1212

GMAT Forum Director

Joined: 18 Apr 2019

Last visit: 01 May 2026

Posts: 938

Own Kudos:

1,362

[1]

Given Kudos: 2,218

GMAT Focus 1: 775 Q90 V85 DI90 Verified score

Products:

Expert

Expert reply

GMAT Focus 1: 775 Q90 V85 DI90 Verified score

Posts: 938

Kudos: 1,362

[1]

30 Dec 2025, 15:06

Kudos

Bookmarks

I think egmat has done a good job explaining this and as rightly pointed out, the frequency of these events isn’t something you really need to factor in when solving such questions. I appreciate the effort you put into mathematically deriving the numbers, but those calculations can be adjusted either way depending on the outcome you want to show, which makes them a bit unreliable for a concrete conclusion.

Also keep in mind that most GMAT strengthen or weaken questions involve multiple missing assumptions. Adding one necessary assumption doesn’t make the argument airtight, since it isn’t sufficient on its own. So even after you select the correct option, some gaps will still remain. That’s why the focus should be on the choice that 'most' strengthens or undermines the argument.

D weakens the argument by questioning the reliability of the evidence, which is usually one of the weakest types of weakeners on the GMAT and, as previously discussed, leaves much more room for debate. Many times, words like 'maybe' or 'significantly' end up tipping the balance clearly in favor of one option.

redandme21

DhanyaAbhirami

Joined: 09 Mar 2024

Last visit: 16 Mar 2026

Posts: 55

Own Kudos:

Given Kudos: 14

Products:

Posts: 55

Kudos: 43

22 Jan 2026, 00:25

Kudos

Bookmarks

Wider Range Species = widespread species = species with broader geographic ranges = species with larger habitat ranges
Narrow Range Species = species with more localized habitats = species with limited distribution
short term problems = localized environmental disturbances
long term problems = evolutionary timescales

FACT : One explanation is that widespread species are more resilient to localized environmental disturbances, such as droughts or disease outbreaks.
In short term, MOST Wider Range Species Survival > MOST Narrow Range Species Survival

OPINION : In analyzing the fossil record, paleontologists have found that species with broader geographic ranges tend to survive longer than those with more localized habitats. Consequently, researchers argue that species with larger habitat ranges are more likely to persist over evolutionary timescales than those with limited distribution.
In long term, MOST Wider Range Species Survival > MOST Narrow Range Species Survival

A. Species with broad geographic ranges often experience high levels of genetic divergence across subpopulations, making them more vulnerable to speciation and eventual extinction.
No comparison done, ignore

B. Several species that went extinct during past global extinction events had significantly larger habitat ranges than many surviving species.
In long term, MANY Wider Range Species Survival < Narrow Range Species Survival
Opposite, hold

C. Localized species are often better adapted to niche ecosystems and may evolve specialized traits that increase their chances of surviving specific environmental changes.
In short term, Wider Range Species Survival < SOME Narrow Range Species Survival
Exception to fact, doesn't attack conclusion, weak weakener

D. Fossil evidence is incomplete and may overrepresent species with larger ranges, which are more likely to leave behind fossil traces across regions.
Questions the evidence, weak weakener

E. Some species with limited geographic ranges have persisted for tens of millions of years without significant change.
In long term, Wider Range Species Survival <= SOME Narrow Range Species Survival
Exception to conclusion, weak weakener

Ans is B

gullyboy09

Joined: 13 Oct 2025

Last visit: 01 May 2026

Posts: 152

Own Kudos:

Given Kudos: 38

Products:

Posts: 152

Kudos: 8

20 Apr 2026, 09:30

Kudos

Bookmarks

Hi Bunuel, MartyMurray, can you please help me with this question. What my understanding of this question was one observation was given - "paleontologists have found that species with broader geographic ranges tend to survive longer than those with more localized habitats.", and why this is happening, explanation followed in the passage.

Now question was undermining the reasoning, means, we should try to weaken the reason given (i.e. explanation). Now this can be done by weakening the explanation itself or finding alternative explanation. But what D does is, it destroys the premise instead. I had assumed that what paleontologists observed is true but explanation given for this phenomenon is something we need to weaken. Can you please help me with this query? D doesn't undermine the "reasoning".

In analyzing the fossil record, paleontologists have found that species with broader geographic ranges tend to survive longer than those with more localized habitats. One explanation is that widespread species are more resilient to localized environmental disturbances, such as droughts or disease outbreaks. Consequently, researchers argue that species with larger habitat ranges are more likely to persist over evolutionary timescales than those with limited distribution.

Which of the following, if true, most seriously undermines the reasoning in the argument above?

A. Species with broad geographic ranges often experience high levels of genetic divergence across subpopulations, making them more vulnerable to speciation and eventual extinction.
B. Several species that went extinct during past global extinction events had significantly larger habitat ranges than many surviving species.
C. Localized species are often better adapted to niche ecosystems and may evolve specialized traits that increase their chances of surviving specific environmental changes.
D. Fossil evidence is incomplete and may overrepresent species with larger ranges, which are more likely to leave behind fossil traces across regions.
E. Some species with limited geographic ranges have persisted for tens of millions of years without significant change.