It is theoretically possible that bacteria developed on Mars early in

ANALYZE THE STIMULUS:

Fact: It is theoretically possible that bacteria developed on Mars early in its history and that some were carried to Earth by a meteorite.
Fact: no two bacterial strains on Earth are different enough to have arisen on different planets.
Conclusion: So______________________________________________.

(What would be the best option to complete the passage?)

NOTE: When you see signal words such as so, thus, therefore, hence,.... ==> think about conclusion. So, this question is absolutely main point question.

ANALYZE EACH ANSWER:

A. Whether or not bacteria actually developed on Mars.
Wrong. A is not main point. If you read the stimulus again, clearly A is not the main conclusion at all.

B. Its likely it is that Martian bacteria were transported from Earth.
Wrong. SHELL GAME. Please read B one more time. B is a reverse answer that says bacteria were transported to Mars FROM Earth.

C. Martian bacteria could have been carried to Earth by means other than meteorites.
Wrong. Nothing about other means.

D. All bacteria now on Earth could have arisen from transported Martian bacteria.
Correct. Because all bacteria on Earth seem to be originated from ONE source. Thus, they could have transported from Mars.

E. There could have been strains of bacteria that originated on Earth and later died out.
Wrong. Not relevant. Do not infer too far. This is MAIN POINT question that only accepts information in the stimulus (the main difference from weaken/strengthen question that accept "new" information).

Hope it helps.

D

IF they all are from Mars, and none from Earth, even then all bacterial strains can be similar and derived from the one that came from Mars.

D for the same reason as given by Indy

Mars (Fill in): It is theoretically possible that bacteria developed on Mars early in its history and that some were carried to Earth by a meteorite. However, strains of bacteria from different planets would probably have substantial differences in protein structure that would persist over time, and no two bacterial strains on Earth are different enough to have arisen on different planets. So______________________________________________.
(What would be the best option to complete the passage?)
A. Whether or not bacteria actually developed on Mars.
B. Its likely it is that Martian bacteria were transported from Earth.
C. Martian bacteria could have been carried to Earth by means other than meteorites.
D. All bacteria now on Earth could have arisen from transported Martian bacteria.
E. There could have been strains of bacteria that originated on Earth and later died out.

I find this quite tricky and have no OA at all. Plz give ur comments and OA if possible.Many thanks.

To me it is between B or D. As both option provide clue that it is essentially same bacteria strain in Martian planet as well as Earth.
However D uses word All, so I will say it is extreme.

Hence I will go with B.

I would go with D here.

You need the presense of the word 'All' to exclude the possibility that there exists Earth and Martian bacteria here on earth. This is because in the paragraph, it states that there is no two strains of bacteria that are different enough to have come from another planet. But, what if all the bacteria on Earth came from Mars originally? Then we would have no way of point of reference to compare Martian and Earth bacteria. Hence... D.

Option D and E are very close.
E is relevant but none of the premise are closely related to the existence of bacteria that originated in earth .

B for me

Here is my reasoning;

It is theoretically possible that bacteria developed on Mars early in its history and that some were carried to Earth by a meteorite. . the opening sentence sets the tone (two different types of bacteria being discussed that of Mars and that of the Earth) Eliminate any answer choice that does not refer to both Martian bacteria or Earth Bacteria (A, E).

However, strains of bacteria from different planets would probably have substantial differences in protein structure that would persist over time, and no two bacterial strains on Earth are different enough to have arisen on different planets.
An opposing thought. "no two bacterial strains on Earth are different enough to have arisen on different planets".

Hence B "since no two bacterial strains on earth are different" and also "strains of bacteria from different planets would probably have substantial differences in protein structure that would persist over time". Its likely it is that Martian bacteria were transported from Earth.

besides D is to extreme (be wary of extreme words such as all, only, always etc)

this one is a GMAT prep question. read this today and my mind went back to this question. lol - so it was true all along...

NASA: Unearthly bacteria detected on three meteorites

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By Reuters
Monday, March 7, 2011

WASHINGTON -- A NASA scientist reports detecting tiny fossilized bacteria on three meteorites and maintains these microscopic life forms are not native to Earth.

If confirmed, this research would suggest life in the universe is widespread and life on Earth may have come from elsewhere in the solar system, riding to our planet on space rocks like comets, moons and other astral bodies.

The study, published online late Friday in The Journal of Cosmology, is considered so controversial that it is accompanied by a statement from the journal's editor seeking other scientific comment, which is to be published starting today.

The central claim of the study by astrobiologist Richard Hoover is that there is evidence of microfossils similar to cyanobacteria -- blue-green algae, also known as pond scum -- on the freshly fractured inner surfaces of three meteorites.

These microscopic structures had lots of carbon, a marker for Earth-type life, and almost no nitrogen, Hoover said Sunday.

Nitrogen can also be a sign of Earthly life, but the lack of it only means that whatever nitrogen was in these structures has decomposed out into a gaseous form long ago, Hoover said.

"We have known for a long time that there were very interesting biomarkers in carbonaceous meteorites and the detection of structures that are very similar ... to known terrestrial cyanobacteria is interesting in that it indicates that life is not restricted to the planet Earth," Hoover said.

Hoover, based at NASA's Marshall Space Flight Center in Alabama, has specialized in the study of microscopic life-forms that survive extreme environments such as glaciers, permafrost and geysers.

He is not the first to claim discovery of microscopic life from other worlds.

In 1996, NASA scientists presented research indicating a 4-billion-year-old meteorite found in Antarctica carried evidence of fossilized microbial life from Mars.

The initial discovery of the Mars meteorite was greeted with acclaim, and the rock was unveiled at a standing room-only briefing in NASA headquarters in Washington.

Since then, however, criticism has surrounded that discovery, and conclusive proof has been elusive.

Hoover's research may well meet the same fate. In a statement published with the online paper, The Journal of Cosmology's editor in chief, Dr. Rudolf Schild, said in a statement: "Dr. Richard Hoover is a highly respected scientist and astrobiologist with a prestigious record of accomplishment at NASA.

"Given the controversial nature of his discovery, we have invited 100 experts and have issued a general invitation to over 5,000 scientists from the scientific community to review the paper and to offer their critical analysis."

Read more: NASA: Unearthly bacteria detected on three meteorites - Pittsburgh Tribune-Review https://www.pittsburghlive.com/x/pittsbu ... z1Fv6bzPTG

Extreme word like ' ALL ' ( GMAT does not like only , Never , All etc , So why for this one ? ) literally drags me out not to choose D as the potential answer .

I got this right, but this is shockingly written if it is actually a GMATPrep question. The first answer choice doesn't make sense at all.

Note that this is an inference question

ANSWER CHOICE ANALYSIS -

A) It is certain in the first sentence that bacteria originated on Mars
B) Bacteria was created on Mars as per first sentence
C) Other means not mentioned in the argument
D) CORRECT
E) Bacteria which originated on earth not mentioned in the passage

This is such a poorly written question. Is it official?

The tag reports the official software.

What are your reasons for why it is a poorly written question?
_________________

Choice (A) makes no sense at all. Here: So whether or not bacteria actually developed on Mars.

Is that a complete sentence? What does it mean?

So ________.(A) Whether or not bacteria actually developed on Mars.

So = Therefore

based on what the sentence tells us before (strains and so on) we are not sure (whether or not that is used to say is not important which of TWO possibilities is true or not = regardless the reasons)

bacteria = subject

developed = verb

on mars = on mars answer our question WHERE which is used as a conjunction

And yes, it is a complete sentence

I hope this helps
_________________

To complete the passage logically, you should provide a statement that follows from the information given in the passage. The passage discusses the possibility of bacteria developing on Mars and being transported to Earth. It also addresses the differences in protein structure.

The passage ends abruptly, so it needs a concluding statement. Based on the information provided, the most appropriate option to complete the passage is:

(D) All bacteria now on Earth could have arisen from transported Martian bacteria.

This option logically follows from the earlier statements in the passage, as it suggests that Martian bacteria could have given rise to all the bacteria currently on Earth, despite the differences in protein structure.

GMATNinja : could you please explain why B option is wrong?

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