Some soil scientists have asserted that decaying matter on the forest

Question

Some soil scientists have asserted that decaying matter on the forest floor is a far greater source of the acidity in mountain lakes than is the acid rain that falls on these lakes. Therefore, they contend, reducing acid rain will not significantly reduce the acidity levels of mountain lakes.

Which of the following statements, if true, most seriously weakens the argument above?

(A) It is natural for mountain lakes to have acidity levels higher than those of other lakes.
(B) The harmful effects of increased acidity levels in lakes have been greatly underestimated.
(C) Acid rain is found in urban and heavily industrialized regions of the country.
(D) There is much disagreement among soil scientists about the causes of acid rain.
(E) While plant life remains, acid rain significantly increases the amount of decaying organic matter in natural environments.

Kudos  for the right answer and explanation

ArupRS · Answer

E is the correct answer. AS per the arguments, it seems occurrence of acid rain and decaying matter cause acidity separately. If we can how somehow that both are correlated we can weaken the conclusion. hence option E is correct. it tells Acid rain causes or enhances decaying of matter which causes acidity in the lakes.

monk123 · Answer

Some soil scientists have asserted that decaying matter on the forest floor is a far greater source of the acidity in mountain lakes than is the acid rain that falls on these lakes. Therefore, they contend, reducing acid rain will not significantly reduce the acidity levels of mountain lakes.

CONCLUSION: reducing acid rain will not significantly reduce the acidity levels of mountain lakes
REASONING: We need to find the answer choice which shows reducing acid rain will reduce the acidity in the mountains. Ans acid rain is the contributor behind the increased acidity.
  
Which of the following statements, if true, most seriously weakens the argument above?

(A) It is natural for mountain lakes to have  acidity levels higher than those of other lakes . - no such comparison
(B) The  harmful effects of increased acidity levels  in lakes have been greatly underestimated. - out of scope
(C) Acid rain is  found in urban and heavily industrialized regions  of the country. - out of scope
(D) There is much disagreement among soil scientists about the  causes of acid rain . - out of scope
(E) While plant life remains,  acid rain significantly increases the amount of decaying organic matter  in natural -   AND THIS DECAYING MATTER IS THE GREATER SOURCE OF ACIDITY IN LAKES. THUS, REDUCING ACID RAIN WILL REDUCE ACIDITY LEVELS OF MOUNTAIN LAKES. - CORRECT

jaisonsunny77 · Answer

this passage says that there are two sources that cause acidity in mountain lakes : 
(i) decaying matter on the forest floor
(ii) acid rain

The passage also lets us know that the 'decaying matter' causes far greater acidity than the acid rain itself. The passage then goes on to make the conclusion that 'eliminating acid rain WILL NOT reduce the acid levels of mountain lakes'.

To weaken this conclusion, we need to come up with an option that shows that "acid rain certainly affects the acidity levels of mountain lakes to some great extent, one way or the other".

Now, let us look for an answer choice that does exactly this.

(A)  It is natural for mountain lakes to have acidity levels higher than those of other lakes.  - knowing (A) as a fact does nothing to weaken the idea that 'acid rain reduction does not help reduce the acid levels'. Hence,   (A) is incorrect.

(B)  The harmful effects of increased acidity levels in lakes have been greatly underestimated.  - Even after considering this as true, it still does nothing to weaken the idea that elimination acid rain will have the intended benefits (as described in the conclusion). hence, (B) is incorrect. So,   eliminate (B).

(C)  Acid rain is found in urban and heavily industrialized regions of the country.  - acid rain in urban and heavily industrialized areas is not related to what happens in the mountain lakes (in the context of this passage). (C) is therefore irrelevant. Hence,   Eliminate (C)

(D)  There is much disagreement among soil scientists about the causes of acid rain.  - A simple disagreement (between scientists) still does nothing to weaken the conclusion. hence,   Eliminate (D). 
 
(E)  While plant life remains, acid rain significantly increases the amount of decaying organic matter in natural environments.  - This is the most interesting answer choice among the list. We already know that existing decaying matter on forest floor is a source that causes acidity in the mountain lakes. If acid rain increases the amount of such decaying matter, then the quantity of the source of acidity increases. When the amount of acidity source increases, the acidity levels at the mountain lakes are bound to increase further. Hence, by eliminating acid rain, we will be able to stop the growth of additional decaying matter on the forest floor, thereby preventing a further increase in the acidity levels of mountain lakes. This weakens the conclusion that 'reducing acid rain doesn't reduce the acid levels of mountain lakes. Hence,   (E) is the correct answer.

bronaugust · Answer

To solve this question, let us deploy    IMS's four-step technique   .

STEP #1  ->   IDENTIFY THE QUESTION TYPE

Let us read the question step to identify the question type. The stem states, 'Which of the following statements, if true, most seriously weakens the argument above?' What we have is a  weakening  question.

Now that the question type is identified, let us proceed to the second step.

STEP #2  ->   DECONSTRUCT THE ARGUMENT

In a weakening question, it is a must to deconstruct the argument by figuring out the conclusion and the premise. Let us therefore read the argument and deconstruct it.

CONCLUSION:   Reducing acid rain will not significantly reduce the acidity levels of mountain lakes.
  PREMISE:   Decaying matter on the forest floor is a far greater source of the acidity in mountain lakes than is the acid rain that falls on these lakes.

Now that the argument is deconstructed, let us proceed to the third step.

STEP #3  ->   FRAME A SHADOW ANSWER

To frame a shadow answer, we need to know what the right answer should do. In this question, the right answer must weaken the soil scientists' argument that reducing acid rain will not significantly reduce the acidity levels of mountain lakes.

SHADOW ANSWER:   Any situation that indicates reducing acid rain may significantly reduce the acidity levels of mountain lakes.

Now that a shadow answer is framed, let us proceed to the final step.

STEP #4  ->   ELIMINATE INCORRECT OPTIONS

Answer options that do not match the shadow answer can be eliminated.

(A) It is natural for mountain lakes to have acidity levels higher than those of other lakes. -   NOT A MATCH   -  This option does not indicate that reducing acid rain may reduce the acidity levels of mountain lakes.  -   ELIMINATE

(B) The harmful effects of increased acidity levels in lakes have been greatly underestimated. -   NOT A MATCH   -  Whether or not the harmful effects of increased acidity levels in lakes have been greatly underestimated is irrelevant to the argument.  -   ELIMINATE

(C) Acid rain is found in urban and heavily industrialized regions of the country. -   NOT A MATCH   -  The argument does not concern itself with where acid rain can be found.  -   ELIMINATE

(D) There is much disagreement among soil scientists about the causes of acid rain. -   NOT A MATCH   -  We are worried about the implications of acid rain, not the causes.  -   ELIMINATE

(E) While plant life remains, acid rain significantly increases the amount of decaying organic matter in natural environments. -   MATCHES THE SHADOW ANSWER   -  If while plant life remains, acid rain significantly increases the amount of decaying organic matter in natural environments, decaying matter on the forest floor will witness an increase, and since decaying matter is a source of the acidity in mountain lakes, acidity levels of mountain lakes will increase; in other words, reducing acid rain may significantly reduce the acidity levels of mountain lakes.  -   KEEP

Hence, (E) is the right answer.

Some soil scientists have asserted that decaying matter on the forest

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Some soil scientists have asserted that decaying matter on the forest

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