Each of these choices is offered as a potential conclusion to the argument.

That argument, so far, breaks down like this:

• Not all life depends on energy form sunlight. (for example...)
• ...Microbial life has been found in bedrock more than 5 KM below the Earth's surface.
• ...Bacteria have been found on the deep ocean floor, feeding on gases rising from the Earth's interior.

Now, which choice most follows as the logical conclusion to these statements?


Choice (C) states that if you thoroughly survey (i.e., examine) the surface of a planet, the information gained from that survey won't be enough to confirm that there is no life on this planet.

Surveying the surface of a planet, by definition, does not examine whether or not there is life below the surface. Even a thorough survey of the surface would not include, say, bacteria on deep ocean floors or microbial life 5km below the surface.

(C) follows logically from the prior statements because the prior statements tell us that life can exist far below the surface of a planet (in this case, Earth):

• Not all life depends on energy form sunlight. For example...
• ...Microbial life has been found in bedrock more than five KM below the Earth's surface.
• ...Bacteria have been found on the deep ocean floor, feeding on gases rising from the Earth's interior.
• Therefore, a thorough survey of a planet's surface is insufficient to establish beyond a doubt that the planet contains no life.

Looking at this another way, why is the author writing any of this in the first place? The author has just spent three lines and presented two pieces of evidence in order to show us that not all life depends on energy from sunlight. That's why (C) is such a good fit.

Now, let's take a look at choice (D):


Hm, well, we have no reason to question whether (D) is true or false... but that's irrelevant. Our task is to decide whether (D) fits into the passage as a logical conclusion to what the author's already presented. And this statement has no connection to the why of this passage.

Following up these statements with a conclusion that life probably exists on Sun-orbiting comments would be a wild logical detour that does nothing to build on the argument that the author has been building so far. That's why we eliminate (D).

I hope this helps break through the surface of this question! (I know... bad joke. I'm still working on my dad jokes. This one was bad enough to qualify, right?)
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Not all life depends on energy from sunlight.
Microbial life has been found in bedrock more than five kilometers below the surface of the Earth,
Bacteria have been found on the deep ocean floor feeding on hydrogen and other gases rising from the interior of the Earth through vents in the ocean floor.

So the main idea is that life can thrive on other energy resources too. It doesn't necessarily need sunlight.

We need a conclusion.

(A) The location in the bedrock where microbial life was found was not near a system of volcanic vents through which hydrogen and other gases rose from the interior of the Earth.

We cannot conclude that the bedrock was not near volcanic vents. Nothing in our premises support that.

(B) Bacteria are able to exist at the molten center of the Earth.

Nothing is mentioned about molten centre of the Earth. We don't know if the parameters on the centre allow life to survive.

(C) A thorough survey of a planet's surface is insufficient to establish beyond a doubt that the planet contains no life.

Correct. The premises tell us that that life can survive in the deep interiors of the planet too that don't get sunlight. This implies that a survey of the planet surface is not enough to say whether the planet contains life. It may be that life survives deep inside the planet.

(D) Life probably exists on Sun-orbiting comets, which are cold agglomerations of space dust and frozen gases.

Nothing in the premises tell us that life probably exists on cold agglomerations. All we know is that sunlight is not necessary. But there may be other things that are necessary but these cold agglomerations do not have.

(E) Finding bacterial remains in coal and oil would establish that the bacteria had been feeding on substances that had not been produced from the energy of sunlight.

Finding bacterial remains (not bacteria, their remains) in coal and oil tells us nothing about those bacteria when they were alive. What if these bacteria were living on the surface on leaves and died there itself. Finally when the plants fell into the earth, they converted into coal over millions on years. Upon extraction of that coal, finding bacteria remains does not tell us that the bacteria were not feeding on sunlight. We do not know how the remains came into the coal. We cannot say using our argument that finding bacterial remains in coal would establish anything.

Answer (C)
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I get C.

Life can exist without sunlight (which is only visible on the surface).

Example of life in bedrock (not on surface)

Example of life on ocean floor (not on surface)

Therefore:

Surveying the surface to determine if a planet contains life is insufficient.

Clear C.

A. Don't know anything about volcanic vents
B. Don't know anything about molten center of Earth
C. Correct -- Bacteria has been found well below the surface of the Earth
D. Probably is too strong -- Passage gives no sense of probability
E. The bacteria itself does not need direct sunlight but could be feeding on sunlight-produced substances that trickled down from the Earth's surface

Not all life depends on energy from sunlight. Microbial life has been found in bedrock more than five kilometers below the surface of the Earth, and bacteria have been found on the deep ocean floor feeding on hydrogen and other gases rising from the interior of the Earth through vents in the ocean floor.

The statements above, if true, best support which of the following as a conclusion?

(A) The location in the bedrock where microbial life was found was not near a system of volcanic vents through which hydrogen and other gases rose from the interior of the Earth. -> this is incorrect as conclution since it does not present the main point of not all life depends on sunlight

(B) Bacteria are able to exist at the molten center of the Earth. -> this is just an evidence not a conclution

(C) A thorough survey of a planet's surface is insufficient to establish beyond a doubt that the planet contains no life. -> this is apt since from the above passage we know main point is not all life depends o sunlight and evidences are of microbes,bacteria.Hence just looking at surface species presence we cannot comment on life on a planet .deep oceans and underneath earth need to be looked into

(D) Life probably exists on Sun-orbiting comets, which are cold agglomerations of space dust and frozen gases. -> OOS

(E) Finding bacterial remains in coal and oil would establish that the bacteria had been feeding on substances that had not been produced from the energy of sunlight. -> Just an evidence

My take: E

Conclusion is " Not all life depends on energy from sunlight" and as per Powerscore Bible, the answer to this question should be related to the conclusion.
Option E, clearly supports that bacteria's have been found in coal and oil and do not require energy from sunlight...

Please correct me if i am wrong...

OA:C (as per OG11)

Initially I chose (E).However, I was mislead to the answer as choice (C) clearly states that just surveying the surface for existence of life is wrong.Nevertheless, option (C) indirectly states the conclusion that is mentioned in the first line of the given passage.

(C). Some life exists even under the surface => Just surveying surface won't do=> Not all life depends on energy from sunlight.

Hope it helps

Rgds,
TGC !!

E strengthens the argument. Conclusion should either summarize what is stated in the premises or use the premises as facts to prove a point. E serves as an evidence to support the fact "Not all life depends on energy from sunlight".

C is correct here. It captures the essence of the premises. Since organisms have been found to survive beyond the surface of earth, it could be the case of any other planet as well. Hence, a survey on the surface of any planet is insufficient to ascertain the non-existence of life in that planet.

GMATNinja, can you please explain the meaning of 'C', how to interpret it and why is it the correct answer? Why is the thorough survey insufficient?
Also why is option 'D' wrong? Is it because we can't be sure if the life on those orbits is subjected to sunlight or not? Also would love to hear your take on how to understand the entire argument.

GmatNinja can u help with elimination of option B ? If "Bacteria are able to exist at the molten center of the Earth" then it supports the conclusion that sunlight is not essential.

Option B takes things to the other extreme which is neither suggested nor supported by the passage. Sure, it talks about 5km beneath the surface and ocean floors. But talking about existing at the earth's center is too much of an extrapolation to make.
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Take a close look at the exact wording of the question:

Here, we're not trying support a conclusion that's already part of the passage. Instead, we have to choose the answer choice that is supported BY the information in the passage.

The information in the passage doesn't support the conclusion that "bacteria are able to exist at the molten center of the Earth," so (B) is not the answer to this question. Take a look at this post for an explanation of the correct choice.

I hope that helps!
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Below are the main points:
Life does not depends on sunlight , examples:
1. Microbial life found under the surface of Earth.
2. Bacteria found on deep ocean
This tells us that life exists on surface (under sunlight), deep oceans(without sunlight) , interior of Earth

Choice:
(A) The location in the bedrock where microbial life was found was not near a system of volcanic vents through which hydrogen and other gases rose from the interior of the Earth.
-- Incorrect , as it does not talk about Volcanic vents

(B) Bacteria are able to exist at the molten center of the Earth.
-- Incorrect , as it does not talk about molten center , it has considered deep oceans and interior of earth.

(C) A thorough survey of a planet's surface is insufficient to establish beyond a doubt that the planet contains no life.
-- Correct , as it is actually telling us that life not only exists on surface, but also in deep oceans and interior of Earth where the sunlight is not present.

(D) Life probably exists on Sun-orbiting comets, which are cold agglomerations of space dust and frozen gases.
-- Incorrect out of scope , as it is not talking about comets.

(E) Finding bacterial remains in coal and oil would establish that the bacteria had been feeding on substances that had not been produced from the energy of sunlight.
-- Incorrect , we cannot infer that anything having bacterial remains is not produced from energy of sunlight. Also this is out of scope as it does not talk anything about substances produced or not produced by the energy of sunlight.

egmat VeritasKarishma GMATNinja GMATNinjatwo
Could you please explain why choice D and E are not the right one to select? What's wrong with each of them?
Appreciate your favor

E is incorrect because we can't say finding bacterial remains in coal and oil would establish that bacteria had been feeding on substances that had not been produced from the energy of sunlight.

In the passage we're told that not all life depends on energy from sunlight. We're then given an example in which bacteria has been found where sunlight is absent.

Is it established that the bacteria had been feeding on substances that had not been produced from the energy of sunlight? No. Notice the passage doesn't mention anything about where the coal and oil is found -- we have to make a lot of assumptions for this choice to work.

C, on the other hand, is best supported by the information given in the passage: A thorough survey of a planet's surface is insufficient to establish beyond a doubt that the planet contains no life.
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Correct Option C

Conclusion: Not all life depends on energy from sunlight.
Premise - Microbial life has been found in bedrock more than five km below the surface of the Earth, and
Premise - Bacteria have been found on the deep ocean floor feeding on hydrogen and other gases rising from the interior of the Earth through vents in the ocean floor.
Argument: does really not all life depend only on energy from sun, there could be another some more source too.

The statements above, if true, best support which of the following as a conclusion?

(A) The location in the bedrock where microbial life was found was not near a system of volcanic vents
through which hydrogen and other gases rose from the interior of the Earth.
Wrong: Supports premise, not to conclusion

(B) Bacteria are able to exist at the molten centre of the Earth.
Wrong: Supports premise, not to conclusion

(C) A thorough survey of a planet's surface is insufficient to establish beyond a doubt that the planet contains no life.
Correct: this supports the conclusion, that some another organism could depend on other form of energy, which can be found in all location, like surface, bedrock, deep ocean and other location, where life is yet to be found

(D) Life probably exists on Sun-orbiting comets, which are cold agglomerations of space dust and frozen gases.
Wrong: Irrelevant, No information about it in passage

(E) Finding bacterial remains in coal and oil would establish that the bacteria had been feeding on substances that had not been produced from the energy of sunlight.
Wrong: Supports premise, not to conclusion

VeritasKarishma GMATNinja Can you please explain why E is wrong? E clearly supports the premise. How could it be wrong? I can see why c is correct. Please do explain.

Thanks

Not all life depends on energy from sunlight. Microbial life has been found in bedrock more than five kilometers below the surface of the Earth, and bacteria have been found on the deep ocean floor feeding on hydrogen and other gases rising from the interior of the Earth through vents in the ocean floor.

The statements above, if true, best support which of the following as a conclusion?

(A) The location in the bedrock where microbial life was found was not near a system of volcanic vents through which hydrogen and other gases rose from the interior of the Earth. -> It is still irrelevant to conclusion. Incorrect.

(B) Bacteria are able to exist at the molten center of the Earth. -> Irrelevant again to conclusion. Incorrect.

(C) A thorough survey of a planet's surface is insufficient to establish beyond a doubt that the planet contains no life. -> Look at the word "insufficient". It means, by checking earth's surface, we can't conclude as there is no life at planet. It say's, life can exit below the surface, where sunlight doesn't reach. It makes sense.

(D) Life probably exists on Sun-orbiting comets, which are cold agglomerations of space dust and frozen gases. -> Life without sun energy is still untouched. Incorrect.

(E) Finding bacterial remains in coal and oil would establish that the bacteria had been feeding on substances that had not been produced from the energy of sunlight. -> This is an example, but still C is better, because, this option is not so direct to impact the conclusion. Incorrect.

So, I think C.

(A) The location in the bedrock where microbial life was found was not near a system of volcanic vents through which hydrogen and other gases rose from the interior of the Earth.
It may or may not be the case we cannot decide therefore out

(B) Bacteria are able to exist at the molten center of the Earth.
We have no clue whether 5 km below we have molten substances therefore out

(C) A thorough survey of a planet's surface is insufficient to establish beyond a doubt that the planet contains no life.
Since we have found life elsewhere other than the surface the conclusion is therefore worth while therefore let us hang on to it

(D) Life probably exists on Sun-orbiting comets, which are cold agglomerations of space dust and frozen gases.
This is a far fetched conclusion this may or may not be true therefore out

(E) Finding bacterial remains in coal and oil would establish that the bacteria had been feeding on substances that had not been produced from the energy of sunlight.
There is a possibility that scientista are perfoming a experiment and they are the ones providing photovoltaic energy absence of a evidence doesn't favour in non-existence therefore out

Therefore IMO C