Earth is the one of four terrestrial planets in our solar system – it

Question

Earth is the one of four terrestrial planets in our solar system – it has a rocky exterior. It is, however, the only planet that supports an oxygen rich atmosphere. Scientists plan to create an artificial atmosphere with the ability to sustain oxygen on one of the other terrestrial planets, Mars- a planet currently too cold for inhabitation. Clearly, the rocky surface and oxygen should allow Mars to sustain humans.

Which of the following is an assumption upon which the argument depends?

Which of the following is an assumption upon which the argument depends?

A) There is readily usable water on Mars.
B) Mars has enough rocky surface to support all humans on Earth.
C) It would be possible for humans to eventually travel to Mars.
D) The new atmosphere wouldn’t further lower the temperature of Mars.
E) Mars was an inhabitable planet millions of years ago.

Source - FloatingGMAT

AdityaHongunti · Answer

To be honest I find some inconsistencies and flaws in the answer choices.

The argument is all about two things Viz., Oxygen and rocky surface , making the planet habitable...

The first thing that comes to my mind is that we are given that the Mars is too cold... But we are nowhere given that that temperature is necessarily harmful for humans and/or cannot be dealt with...

So my assumption would be that the original temperature (too cold) is not a problem for habitation...

Answer choice D says that the oxygen would not be a problem... Fine... But what about the original temperature?? (Without oxygen)...is that okay for habitation???

I think the assumption needs to be absolutely true...

Let's negate D, the oxygen will further lower the temp...
But are we sure that this temperature is harmful to the humans?? If it's not then this assumption anyway doesn't really affect the argument !!

Other answer choices are just poor...I mean out of all answer choice D comes closer...but I don't think it is the NECESSARY ASSUMPTION...

generis  please share your views

Posted from my mobile device

Kartalyst · Answer

Negating (D) doesn't break down the conclusion.
My negated version of D is 'The new atmosphere would further lower the temperature of Mars'. This doesn't mean the lower temperature wouldn't sustain humans.
Is there a flaw in my conclusion? Although I chose D but I'm not convinced it's an assumption.
I need an expert advice, please.

rahulpetrocrat · Answer

I have also zeroed down to choice B and D.
Since it has been already suggested that the temperature is low at Mars and temperature variation doesn't seems that much correct hence i would reject choice D and would choose choice B.

Since Rocky surface condition and oxygen environment is necessary for life at a planet specified the author and since scientist are providing habitable oxygen environment but nothing is mentioned about the rocky surface condition. Hence in my point of view choice B is correct.

However i would wait for some expert advice on it.

generis · Answer

This question tempts readers to import real world assumptions that are entirely reasonable—and not correct because the passage says not one word about those assumptions.

Its correct answer is not great, but it is the least bad of the answers.

• Breaking down the prompt
Fact #1: Earth has a rocky exterior and is therefore terrestrial.
Fact #2: Though 3 other planets are terrestrial, Earth is the only one with a rich oxygen atmosphere.
Fact #3: Scientists will create an artificial atmosphere on terrestrial planet Mars that can sustain oxygen
Fact #4: Mars is currently too cold for human inhabitation
Conclusion: Mars should be able to sustain human beings because it is terrestrial (rocky) and it will have oxygen.

On which answer does the conclusion depend?

Any one of three issues is likely to be the subject of an answer: oxygen, rocky surface area, or cold.

The question mentions nothing about whether water on Mars is an issue. Eliminate
Be careful, whether you "bridge the gap" or use the negation test. 
As far as we know  from the words in this prompt , readily usable water is not an issue.
The prompt does not mention water. Work only from the facts at hand.

Whether a planet has a rocky surface matters; a rocky surface is one of two elements that "should" sustain human life on Mars. 
But the passage did not mention that  all  human beings were going to Mars.
The "all"—a very strong word in CR and RC—is a hint. This option is probably wrong. KEEP, but be careful

Just as in answer A, this assumption is imported from the real world and has nothing to do with the actual words in the question. 
Yes, it must be possible for human beings eventually to travel to Mars. 
But the conclusion is not about getting to Mars. The issue is whether the rocky surface and oxygen on Mars would sustain human life when human beings were on Mars. Eliminate C

This answer is probably correct.

Mars is already too cold for human beings to inhabit. I wondered how scientists would warm up Mars.
This alternative presents an issue that could be interpreted in two ways, but either way, if Mars becomes even colder than it is now, it becomes even less likely to sustain human life.
Both interpretations are more strained than it may seem. 
The reasoning is not straightforward, simple, or easy.

(1) The scientists mention only rocky surface area and oxygen. 
To do so, they must have a solution for the temperature problem.   Whatever solution for all the problems that the scientists face, however, must not make Mars colder.
The scientists are assuming that the solution does not make Mars colder.
(2) The scientists have not yet addressed how to solve the temperature problem and are focused on rocky surface and oxygen, but at the least, no matter what, they cannot get to the oxygen and rocky surface issues if their atmospheric solution makes Mars  more  uninhabitable.

It's true: the cold issue is present before answer D and after answer D. 
The scientists cannot get to the oxygen and rocky surface issues unless they also solve the temperature problem.
Either they already have a solution or they assume that they can find a solution.

Option D just makes an already-obvious problem worse.

If they have a solution to the temperature problem, then they assume that their atmospheric changes will not ruin their solution to the temperature problem.
If they do not have a solution to the temperature problem, then they will need to find one, at which point they must also assume that their solution to the oxygen problem does not make Mars colder.

This part exposes the flaw in the question.
 We cannot infer from an asserted conclusion that a different problem has been solved.  
Whether Mars is cold or colder, the temperature makes it uninhabitable, full stop. 
The issue is not resolved before the conclusion or by the conclusion. (Rocky surface and level of oxygen don't matter if no one can live there because Mars is too cold.)

Answer D is not great, but it is better than B.

Negate the assumption.
 The new atmosphere  would  lower the temperature of Mars. 
Not good. A colder Mars would become the threshold issue; a colder Mars would keep the scientists from asserting anything about other issues and sustainability.
A colder Mars is not even viable.

That is, although the conclusion focuses on oxygen and the rocky surface, the scientists can't conclude anything about rocks and oxygen if people could not live on the planet in the first place because the artificial atmosphere had made the planet colder. 
(It's true that they cannot reach the oxygen and rocky surface issues anyway. But answer D makes that fact a little more clear.)

I am not a fan of this answer, but I think it is correct.

That's nice. The Earth had dinosaurs, too, then. Are they coming back?
Option E is utterly irrelevant.

Option D vs. Option B?

Option B is not as good an answer as D is. 
The prompt did not suggest that Mars had to sustain  all  the people on Earth, as B suggests.
In other words, B is completely disconnected from the conclusion. 
Scientists must assume that the rocky surface can sustain some number of people, 
but they do not have to assume "all," and not one word in the prompt suggests that  all  is an issue.

We are sure that Mars is too cold for people and that therefore Mars cannot get any colder.
We are sure Mars has a rocky surface.

The word "all" is (B) too strong. "All" makes (B) too off-topic.
And it's true: Mars cannot get colder.
(D) is about the possibility that Mars could get colder.
The scientists must be assuming at the least that their artificial atmosphere—whether they have a solution for the temperature problem or not—does not make Mars colder.

Any one of the three problems I listed above could have become the threshold issue. Not enough oxygen? Then rocky surface and temperature do not matter.

Cold temperatures are now the threshold issue: we cannot address rocky surface area or oxygen needs because people can't stay on Mars to find out about the surface area and oxygen.

This question is not very representative of an actual CR. Try not to worry about it.
Go with the answer most connected to the issues in the prompt and the conclusion.

That answer is D

generis · Answer

AdityaHongunti  , this question is tough because the conclusion does not seem to be tied to the premise about the coldness of Mars. I agree with you. The question is flawed. 
 AdityaHongunti  , I've edited my response to you. The more I think about this question, the more I am convinced that it is not representative and not worth worrying about.

The coldness of Mars at best was glossed over in the conclusion, so we have to "back up" to before the conclusion because we do know one thing: 
if Mars gets colder, then we cannot even consider oxygen levels and rocky surface area.

You wrote,  we are given that the Mars is too cold... But we are nowhere given that that temperature is necessarily harmful for humans and/or cannot be dealt with... 
Mars is too cold for people to live on right now.
"Too cold" means that the temperature IS necessarily harmful; the temperature is so harmful that human beings cannot live there as of now.

Your second observation is good: What we are not given is whether the scientists have a solution for the temperature problem (see my answer above) before they draw conclusions about sustainability based on oxygen and rocky surface.

This is good analysis to a point; however, the prompt says that the original temperature of Mars IS a problem.
No one can live there. It's too cold.

Here was your and the other posters' smart move that ends up being frustrating because this CR is odd:  
True, and in fact if the scientists are proclaiming that Mars will have plenty of oxygen and rocky surface area, we could take the "use the most reasonable logic" approach: the scientists must be confident that they can deal with this temperature. Or, when they deal with the temperature issue, when they carry their oxygen and rocky area conclusion with them, they must assume that the artificial atmosphere does not make Mars colder (that atmospheric solution is what they'll carry forward).

I can see how Answer D would seem strange: if coldness is resolvable (maybe that fact is implied in the conclusion?), why wouldn't a little more coldness be resolvable? Answer D is strained. It's the best of five.

No strong explicit connection exists between Mars's too-cold temperatures and the assertions in the conclusion. We cannot infer that an asserted conclusion about oxygen and rocky surface copes with the temperature issue, though on the most reasonable interpretation, it does.

We do not know what the scientists plan to do about the cold. Until we are told otherwise, "possibly colder because of the scientists' plan" becomes the best option available.

Answer D is less wrong than B. Answer B is wrong because of "all."

We have to argue that as a threshold matter, the scientists cannot begin to make assertions about oxygen levels and rocky surface area if their artificial atmosphere makes Mars colder.

That is, cold temperatures now become the threshold issue. I agree that the question is a bit frustrating.

Hope that analysis helps.

generis · Answer

Hi  gbengoose  , as I explained in posts above, the Mars's temperature is too cold, right this moment, to sustain human existence.

Actually, lowering the temperature of Mars—already uninhabitable because it's too cold—does mean that  even lower  temperatures would not sustain human beings.

Too cold to live on now = too cold to live on if it gets colder.

Hope that helps.

generis · Answer

Hi  rahulpetrocrat  , the scientists simply failed to mention what they would do about the too-cold temperatures, but they cannot conclude anything about rocks and oxygen if no one can live on the planet because the planet is too cold.

The word "all" in B is too strong.

Please see my posts above.

Option D is correct.

Hope that helps.

Doer01 · Answer

Hi Folks,
 Simple language, easy to understand.
There are three other planets in our solar system that are rocky. Scientists are trying to create an artificial atmosphere on Mars, which is TOO COLD to inhabit at the moment.
Conclusion is that the rocky surface (1) & oxygen (2) should allow Mars to sustain life.
Gap: Argument shifted from planet being too cold to rocky and oxygen to sustain humans.

Does not fill the gap, Incorrect.
 
ALL humans? conclusion is not about all humans. Incorrect
 
TRAP answer statement. It does sound attractive because if humans are not able to travel to Mars in the first place, whats the point of whole fuss? But thats not what WE are looking for. Incorrect
 
Now this is interesting as it comments something on the temperature of Mars, which is already too low to sustain life. Negating this statement will break the argument. Correct
 
Does not matter.

VerbalBot · Answer

Automated notice from GMAT Club VerbalBot: 

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

 This post was generated automatically.

Earth is the one of four terrestrial planets in our solar system – it

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Critical Reasoning (CR) Questions

Earth is the one of four terrestrial planets in our solar system – it

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards