B

Narrowed down to B and D. I will go with B because if water in many ponds that are contaminated with radioactive elements is cold then the sunflower will not grow and the said process will not be successful.
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Clear winner B.

We are asked to find a limitation to the proposed solution.
B states that most of the radio active contaminated ponds are so cold that sunflowers cannot be grown there.

Bingo B. Dahiya's bang on target.

A. Not important

B. The water in many ponds contaminated with radioactive elements is so cold that it would kill sunflowers whose roots were submerged in it.

C. Not interested in how well sunflowers can be cultivated

D. Not critical as the scientists could propose that large leafed sunflowers be used

E. Not important

B is the best choice. If the roots are killed, then the mechanism to remove the radioactive elements would not be available.

Yup narrowed it down to B and D.

Think B is more of a limitation than D (Sunflowers with large leaves could be found Switzerland ). B - The problem with the water being so cold cannot be replaced with something else.

I was thinking D first, but then B is stronger: if the sunflowers are done, then how the decontamination is going to take place?

B

Sunflowers growing in pots were placed, with their roots submerged, in the pond contaminated with radioactive elements. The sunflowers kept growing; in the process, they absorbed radioactive elements. Within twelve days, 85 percent of the radioactive elements were removed from the water, which is no less than can be accomplished with the much more expensive conventional filtration techniques. Scientists therefore propose using sunflowers for decontamination wherever there are radioactively contaminated ponds.

Which of the following, if true, points to a limitation on the applicability of the proposed method of decontamination?

A. Some plants other than sunflowers can also remove radioactive elements from water. then what we are looking for the sun flower,.. out of scope....

B. The water in many ponds contaminated with radioactive elements is so cold that it would kill sunflowers whose roots were submerged in it. the one

C. Sunflowers that grow with their roots submerged in water grow less well than sunflowers growing under optimal conditions on dry land. not concerned about sun flowers growh but about their decontamination effect on water....

D. Only species of sunflowers with large leaves can have their roots submerged in water and still keep growing. no mention about leaves

E. In ponds in which the circulation of the water is artificially increased, sunflowers absorb radioactive elements far faster than they do in other ponds. then we are not concerned about speed here

ruling everything out stays B up

B. We're interested in problems that limit the application of sunflowers to decontamination. If the sunflowers die due to the cold, they won't work.

E. - raises questions against 12 week period.

Late, but read to (B) and stopped. Perfectly valid limitation. Think of Lake Baikal in Siberia. It`s freezing there, especially in the winter.

:54

The Question stamp does not ask to weaken argument straight away instead uses the word "Limitation". This is why D stands as another contender while B is just correct. Otherwise D is just wrong because mention of "leaves" makes it out of scope and D both supports and weakens.

I chose B because the correct answer choice for a weaken CR question is one that weakens the MOST.

+1 for B.
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Option D doesn't weaken the case. We can use the sunflowers with large leaves and still have the plan successful. B is a clear winner.

The argument clearly mentions that sunflowers kept growing when their roots were submerged in the contaminated water and option b kind of states the opposite.
please explain.

B says (B) The water in many ponds contaminated with radioactive elements is so cold that it would kill sunflowers whose roots were submerged in it.

Not all ponds, sunflowers might be able to survive in the experiment pond, but not in a lot other ponds.

Sunflowers growing in pots were placed, with their roots submerged, in the pond contaminated with radioactive elements. The sunflowers kept growing; in the process, they absorbed radioactive elements. Within twelve days, 85 percent of the radioactive elements were removed from the water, which is no less than can be accomplished with the much more expensive conventional filtration techniques. Scientists therefore propose using sunflowers for decontamination wherever there are radioactively contaminated ponds.

Conclusion: propose using sunflowers for decontamination wherever there are radioactively contaminated ponds.

Which of the following, if true, points to a limitation on the applicability of the proposed method of decontamination?
Weaken question. We have to find the answer for the question: Cannot use sunflowers as a method to absorb radioactive elemets.


(A) Some plants other than sunflowers can also remove radioactive elements from water.
Out of scope. We are talking about sunflowers.

(B) The water in many ponds contaminated with radioactive elements is so cold that it would kill sunflowers whose roots were submerged in it.
This is the correct answer. The sunflower cannot be planted.

(C) Sunflowers that grow with their roots submerged in water grow less well than sunflowers growing under optimal conditions on dry land.
"Grow less well" but at least it is still survive

(D) Only species of sunflowers with large leaves can have their roots submerged in water and still keep growing.
We still have 1 sunflower type for this project.

(E) In ponds in which the circulation of the water is artificially increased, sunflowers absorb radioactive elements far faster than they do in other ponds.
Sunflowers work in these ponds