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# Certain genetically modified strains of maize produce a

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Director
Joined: 20 Sep 2006
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Re: Certain genetically modified strains of maize produce a [#permalink]

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09 Sep 2008, 20:50
1
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IMO C

Maze insecticide -- goes to --> Polen --- thru wind it goes to --> Milkweed --from its leaves it goes to --> Caterpiller and then Caterpiller dies.

We want to make sure this all happens at same time. We dont want the polen to be release during the onth of Jan only and then Caterpiller eating leaves after 6 months. By that time ofcourse the dust from leaves will be gone and that means there is somthing else in leave that is causing Caterpiler to die .. after eating the leaves.

Hope I am on right track and this help...

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Re: Certain genetically modified strains of maize produce a [#permalink]

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09 Sep 2008, 23:42
E for me.

In E, if there are competing maize eating insects that feed on milkweed plants, then even these insects would be dieing. This will help evaluate the argument.

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Re: Certain genetically modified strains of maize produce a [#permalink]

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10 Sep 2008, 02:00
scthakur wrote:
E for me.

In E, if there are competing maize eating insects that feed on milkweed plants, then even these insects would be dieing. This will help evaluate the argument.

exactly Even i was confused between C and E.

Actually only one thing is that ,what if there are enough milkweeds then inspite of competition they leed to death of caterpillars !!!

C is foolproof .
Suggestions welcome
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Re: Certain genetically modified strains of maize produce a [#permalink]

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10 Sep 2008, 08:22
C.

the ques asks if the farmer is putting the monarch butterflies at risk...
E is slightly weaker in the sense that even if maize-eating insects compete with monarch butterflies, it does not completely eliminate the risk of the latter feeding and dying.

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Re: Certain genetically modified strains of maize produce a [#permalink]

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10 Sep 2008, 09:38
prasun84 wrote:
C.

the ques asks if the farmer is putting the monarch butterflies at risk...
E is slightly weaker in the sense that even if maize-eating insects compete with monarch butterflies, it does not completely eliminate the risk of the latter feeding and dying.

But is C not contradicting the argument "Caterpillars of monarch butterflies feed exclusively on milkweed leaves. When these
caterpillars are fed milkweed leaves dusted with pollen from modified maize plants, they
die."

To me C does not provide additional info to help evaluate the argument.....or is it that the argument "when these vaterpillers are fed......" means that these caterpillers are not always fed milkweek leaves?

I am loosing my sense here.

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Re: Certain genetically modified strains of maize produce a [#permalink]

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01 Jan 2009, 15:24
whats the OA here?
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Re: Certain genetically modified strains of maize produce a [#permalink]

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01 Jan 2009, 18:44
C. I would stick with the scope when its confusing. So I ignore "other" insects.
What is OA?

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Re: Certain genetically modified strains of maize produce a [#permalink]

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01 Jan 2009, 18:46
I got C too.

If the CP are feeding during the same time, they are put at risk

If the CP are not feeding at the same time, they are NOT at risk.

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Re: Certain genetically modified strains of maize produce a [#permalink]

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09 Jan 2009, 21:07
Note that the author talks of caterpillars dying from feeding on the leaves laden with pollen but in conclusion, says, all monarch butterflies are in danger. There is a scope shift in the argument. Therefore, to evaluate his conclusion, D sounds the best.

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Re: Certain genetically modified strains of maize produce a [#permalink]

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09 Jan 2009, 21:42
spriya wrote:
Certain genetically modified strains of maize produce a powerful natural insecticide. The
insecticide occurs throughout the plant, including its pollen. Maize pollen is dispersed by
the wind and frequently blows onto milkweed plants that grow near maize fields.
Caterpillars of monarch butterflies feed exclusively on milkweed leaves. When these
caterpillars are fed milkweed leaves dusted with pollen from modified maize plants, they
die. Therefore, by using genetically modified maize, farmers put monarch butterflies at
risk.

Which of the following would it be most useful to determine in order to evaluate the
argument?

A. Whether the natural insecticide is as effective against maize-eating insects as
commercial insecticides typically used on maize are
B. Whether the pollen of genetically modified maize contains as much insecticide as
other parts of these plants
19
C. Whether monarch butterfly caterpillars are actively feeding during the part of the
growing season when maize is releasing pollen
D. Whether insects that feed on genetically modified maize plants are likely to be
killed by insecticide from the plant’s pollen
E. Whether any maize-eating insects compete with monarch caterpillars for the
leaves of milkweed plants growing near maize fields

Many prefer C, but I think C has no effect on the argument. The time caterpillars actively feeing does not matter. The argument cares only the cases that caterpillars feeds "milkweed leaves dusted with pollen", and the pollen is claimed to be responsible for the risk of butterflies.

Only E says something about the leaves! and E is the best
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Re: Certain genetically modified strains of maize produce a [#permalink]

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16 Jul 2013, 22:11
1
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C Correct.
1.monarch butterflies are actually at risk only when they eat milkweed leaves dusted with pollen.
2.so when pollen is not present on milkweed leaves,monarch butterflies safely eat them.
3.so if monarch butterflies are not actively eating milkweed leaves during maize growing season monarch butterflies will be not at risk.

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Re: Certain genetically modified strains of maize produce a [#permalink]

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19 Apr 2014, 14:08
Wouldn't using the "variance test" from Powerscore CR Bible on E mean - Yes the insects compete and use up all the pollen first, therefore the caterpillars don't die. Conversely, No, they don't compete and don't use the pollen therefore the caterpillars will use and die.

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Re: Certain genetically modified strains of maize produce a [#permalink]

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23 Sep 2014, 03:16
1
KUDOS

To solve this kind of evaluate questions, one must do the following:

1.-Understand the argument. For this, one have to read the stimulus very, very closely and literally.

Argument:

Genetically modified maiz produces natural insecticide that will be present even in the pollen.

Pollen is dispersed and reaches milkweed.

Caterpillars die when ARE FED with milkweed leaves.

Conclusion: using this genetically modified maize, butterflies are put at risk.

2.-In evaluate questions, we have to determine which of the answers choices has a content that could impact the conclusion. Evaluate C and E.

C) If we say "Yes, the caterpillars effectively feed on milkweed leaves when these leaves have pollen with insecticide" the conclusion is reinforced. By saying "no, the caterpillars feed on milkweed leaves in a season when leaves do not have pollen with insecticide", the conclusion is clearly weakened: If the caterpillars feed in a time when there is no insecticide in the milkweed leaves, no danger is prompted by using the genetically modified crops.

In here it is important to realize that the stimulus says that caterpillars ARE FED -passive-, but do not suggest anything about the natural behaviour of caterpillars: if the would normally eat leaves when these leaves have insectivide.

E) incorrect. If one affirm the question - yes, they have competitors - there is no impact in the conclusion, because will still do not know when caterpillars feed on milkweed leaves. If we say "no, they have no competitors", the same.

As per the previous post, the fact that E it is the only that explicitly talks about leaves, does not mean that other answers are not talking indirectly about leaves. In fact, C does because it raises the question of when the milkweed leaves have pollen with insecticide.

Hope this helps.

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Re: Certain genetically modified strains of maize produce a [#permalink]

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07 Jan 2015, 05:18

" Caterpillars of monarch butterflies feed EXCLUSIVELY on milkweed leaves "

Which could mean that caterpillar's feed is LIMITED TO MILKWEED LEAVES.

If caterpillars have to LIVE, obviously they have to eat ONLY MILKWEED LEAVES all day all season, since caterpillar's feed is LIMITED TO MILKWEED .

How Option C is right ?

Also please explain in option C , How "actively feeding" is different from "feeding" in the context.

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Re: Certain genetically modified strains of maize produce a [#permalink]

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07 Jan 2015, 21:35
1
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My 2 cents. Though E and C both sound a valid contender, there are couple of reasons to prefer C over E.

Premise:
Certain genetically modified strains of maize produce a powerful natural insecticide.
The insecticide occurs throughout the plant, including its pollen. Maize pollen is dispersed by the wind and frequently blows onto milkweed plants that grow near maize fields.
Caterpillars of monarch butterflies feed exclusively on milkweed leaves. When these caterpillars are fed milkweed leaves dusted with pollen from modified maize plants, they die.

Conclusion:
Therefore, by using genetically modified maize, farmers put monarch butterflies at risk.

Which of the following would it be most useful to determine in order to evaluate the argument?

E. Whether any maize-eating insects compete with monarch caterpillars for the leaves of milkweed plants growing near maize fields
>>There can be multiple possibilities here. It may be that insects compete with MC for leaves when maze r not in pollen phase,, a very small proportion of insects competes with MC Or, insects and MC eats different part of leaves. etc.
If any of these options are true then we can't confidently evaluate the argument. Also C mentions pollen and MC feeding period, a link that is mentioned in premise and a crucial factor to evaluate the argument.

C. Whether monarch butterfly caterpillars are actively feeding during the part of the growing season when maize is releasing pollen.
Yes: Yes it supports the conclusion.
No: Then it weaken the conclusion.

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Re: Certain genetically modified strains of maize produce a [#permalink]

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17 Jan 2016, 12:35
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Re: Certain genetically modified strains of maize produce a [#permalink]

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12 Feb 2016, 23:08
Hello from the GMAT Club VerbalBot!

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Re: Certain genetically modified strains of maize produce a [#permalink]

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03 Jun 2016, 22:21
Argument Analysis :

Certain genetically modified strains of maize produce a powerful natural insecticide. A background information.
The insecticide occurs throughout the plant, including its pollen. A background information.
Maize pollen is dispersed by the wind and frequently blows onto milkweed plants that grow near maize fields. A background information. Milkweed plants – new actor in the argument
Caterpillars of monarch butterflies feed exclusively on milkweed leaves. A background information. Caterpillarsone more actor related to Milkweed plants.
When these caterpillars are fed milkweed leaves dusted with pollen from modified maize plants, they die. A background information – impact of modified strains of maize
Therefore, by using genetically modified maize, farmers put monarch butterflies at risk. Conclusion.

Assumptions -
a. Maize pollen is dispersed by the wind and frequently blows onto milkweed plants.
Assumes that pollens stay as well and wind is not strong enough to disperse pollens in short span of time or may be rain followed by wind to remove the pollens.
b. Caterpillars of monarch butterflies feed exclusively on milkweed leaves:
To remove / reduce the impact of pollens, Milkweed does not produce any natural defense such as chemical etc., which may affect caterpillars.
c. Caterpillars of monarch butterflies feed exclusively on milkweed leaves : maize and milkweed are grown in the same season hence pollens impact the caterpillar feeds.
d. Amount of pollens are significantly enough to impact the caterpillars.

Question stem :
Which of the following would it be most useful to determine in order to evaluate the argument?

A. Whether the natural insecticide is as effective against maize-eating insects as commercial insecticides typically used on maize are – Argument is about impact on caterpillar
B. Whether the pollen of genetically modified maize contains as much insecticide as other parts of these plants – So what only pollens are dispersed
C. Whether monarch butterfly caterpillars are actively feeding during the part of the growing season when maize is releasing pollen –
Yes : then argument is strengthened
No : then argument is weakened

D. Whether insects that feed on genetically modified maize plants are likely to be killed by insecticide from the plants pollen – So what .Impact on other insects is not good enough to conclude about caterpillars
E. Whether any maize-eating insects compete with monarch caterpillars for the leaves of milkweed plants growing near maize fields – Let them compete …where is impact of pollen?

Option C

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Re: Certain genetically modified strains of maize produce a [#permalink]

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27 Jul 2016, 19:28
Conclusion - "Genetically modified maize put monarch caterpillars and in turn monarch butterflies at risk"
Option A - irrelevant
Option B - irrelevant
Option C - keep
Option D - irrelevant
Option E - keep
Apply variance test
Option C - Yes --> In this case maize pollen is the probable cause of death. Substantiates the conclusion
No --> In this case there might be some other causes of death (change of weather etc). Weakens the conclusion
Option E - Yes --> Lets us suppose insect ABC competes with monarch caterpillar. This can have multiple scenarios, what is the number of leaves are substantially more than the combined population of monarch caterpillar and ABC. This hardly effects the conclusion. Other Scenario could be combined population of ABC and monarch caterpillar is equal to the number of leaves. In the event ABC does not die from eating the leaves and monarch caterpillar dies we cannot say leaves are not responsible, maybe anatomy of ABC is different from monarch caterpillar.
From the above information I did not even check for No since option E can be eliminated.
Option C looks best in the choices given.

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Re: Certain genetically modified strains of maize produce a [#permalink]

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22 Dec 2016, 13:35
I like C. Undermines the conclusion if true.

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Re: Certain genetically modified strains of maize produce a   [#permalink] 22 Dec 2016, 13:35

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