#26 - Must Be True

[Administrator]

Complete Question Explanation
(See the complete passage discussion here: lsat/viewtopic.php?t=14217)

The correct answer choice is (C)

This question asks for the likely outcome if the aggressive disease organisms discussed on line 46
were eliminated from land that had been in constant agricultural use. Such disease, researchers
concluded, were the reason that seeds in overfarmed plots did not do as well as those growing in land
that had been out of production for two decades. Presumably, if such disease were to be eliminated,
the seeds would do better, perhaps as well as those growing naturally nearby.

Answer choice (A): There is no basis to conclude that beneficial microorganisms would decline if
the disease organisms were eliminated.

Answer choice (B): The elimination of the disease organisms would not render unwanted species
unable to survive, so this is not the right answer choice.

Answer choice (C): This is the correct answer choice. As discussed, such seeds would likely do
better if the harmful aggressive disease organisms could be eliminated; the native plant would have a
better chance of survival.

Answer choice (D): Nothing in the passage suggests that the elimination of disease organisms in
over-farmed land would result in a long-term increase in the number of beneficial microorganisms.

Answer choice (E): The author does not suggest that eliminating disease microorganisms would be
likely to result in proportional increases in the population of other disease organisms, so this cannot
be the right answer to this Must Be True question.

[lmasta0340]

Hi,

I understand why C is correct, but I am a little confused by the word "beneficial" in this answer choice. I know some microorganisms are beneficial, but I do not see where the passage points out the fact that the native plants are beneficial. Is this supposed to be assumed because the native plants help to prevent thistles?

Thank you in advance!

[KelseyWoods]

Hi lmasta0340!

Yes, the native plants are considered beneficial because they help to prevent thistles, but also because they return the land to its natural ecological system. Also, if native plants were not beneficial, there would not be much point to, or effort put into, restoring those natural plants.

Hope this helps!

Best,
Kelsey

[rosiemoss]

Why is D wrong? Thanks!

[KelseyWoods]

Hi Rosie!

Welcome to the forum and thanks for the question! As stated in the explanation above, answer choice (D) is wrong because there is nothing in the passage to support it. If you can be more specific about why you liked (D) and which part of the passage you think supports that answer choice, then we can help you out with a more specific explanation!

Best,
Kelsey

[cd1010]

Hello -- I was in between C and D. Can you clarify why D is wrong?

I'm looking at the 2nd half of the last paragraph: "Researchers have concluded that this is because fields farmed for many years are overrun with aggressive disease organisms, while, for example, beneficial mycorrhiza–fungi that live symbiotically on plant roots and strengthen them against the effects of disease organisms–are lacking. These preliminary results suggest that restoring natural plant diversity to overfarmed land hinges on restoring a natural balance of microorganisms in the soil."

Basically, I was balancing two things. First is that based on the subsection above, it seemed to me that the more immediate effect of the removal of the diseases is the restoration of balance of micro-organisms in the soil. To me this is closer to what D is saying. However, I wasn't sure about D because of the word "all" (not so much because of the phrase "long-term", as per the explanation above).

My issue with C is that to me the passage implied that this would happen after the soil is restored. OR, that it happens when it is done in conjunction with the sowing of beneficial microorganisms. As the last section of the paragraph says, "In other words, diversity underground fosters diversity aboveground. Researchers now believe that both kinds of diversity can be restored more quickly to damaged land if beneficial microorganisms are "sown" systematically into the soil along with a wide variety of native plant seeds."

Basically, I'm not sure how to pick? Is C correct because the issue with D outweighs the issue that I have with C? Or is my analysis of C not correct?

Thanks!

[Dana D]

Hey cd,

Lines 46-47 refer to plants overrun with disease organisms and lacking any beneficial fungi. The question asks if the aggressive harmful organisms were removed, what would happen? We're also told the land has been in constant agricultural use, meaning the plants should be able to successfully grow there. Therefore, answer choice (C) seems the most likely to be true.

Answer choice (D) is incorrect because we do not know that all typed of beneficial microorganisms will increase - that is a broad statement that may or may not occur. Perhaps just some beneficial microorganisms will repopulate - these lines only reference one type of fungi, mycorrhiza, but we don't know about all species. There is less support for answer choice (D). Hope that helps!