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In Q6, the passage mentions about synchronization in egg-laying patterns of Predator and Prey, so I selected answer choice C, but OA is D. Is it because difference between egg-laying and reproducing activities? as option C says egg-laying while option D says reproducing.
Sajjad1994, can you please help with OA?
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In Q6, the passage mentions about synchronization in egg-laying patterns of Predator and Prey, so I selected answer choice C, but OA is D. Is it because difference between egg-laying and reproducing activities? as option C says egg-laying while option D says reproducing.
Sajjad1994, can you please help with OA?

Explanation

6. The author mentions the egg-laying ability of each kind of mite (lines 20–23) primarily in order to support which one of the following claims?

Difficulty Level: 700

Explanation

Why does the author mention the egg production? If we go back two sentences to lines 17–18, the author is talking about how the Typhlodromus mite population can increase as rapidly as that of the cyclamen mites. So, the egg production information is just support for that claim. That’s answer choice (D).

(A) The rates are not approximately equal. The Typhlodromus mites have a rate practically twice that of the cyclamen mites.

(B) Reproductive life span is Out of Scope. (C), (E) Faulty use of Detail. The ideas of synchrony and slower reproduction in the absence of cyclamen mites don’t come up until later in Paragraph 2, when the author discusses a new factor in the relationship between the mites.

Answer: D
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Saasingh
Can someone explain Q5?

I was confused between C and E but B was not even a contender to me as I POE'd it in the first go. Can't find any reference for it.

TBH I wasn't happy with C too(ONLY after was a red flag for me), but I found it to be the lesser of the evils as I could see why author would think so. Because pesticides "might" have certain disadvantages like severely damaging the crops, using natural predator might be a better first choice and after they fail should we employ the use of pesticides.

I really have no clue where B comes from!! I mean sure it seems reasonable because if predators would kill beneficial insects also, it'll be a problem for agriculture and we would need to maintain caution. But isn't the question a "must be true"? Strictly to stay within scope ? benficial insects is not mentioned anywhere

I rejected E because "generally" is wrong. We just see one case and can't generalize that predators are better than pesticides (nowhere mentioned).

(B) Until the effects of the predators on beneficial insects that live in strawberry fields are assessed, such predators should be used with caution to control cyclamen mite populations.
(C) Insecticides should be used to control certain pest populations in fields of crops only if the use of natural predators has proven inadequate.

You are 100% true in your findings, OA of question #5 was wrongly added as B but actually it is C, I have edited it accordingly.

Thank you.

I don't agree with choice C for 5 either.

5. It can be inferred from the passage that the author would be most likely to agree with which one of the following statements about the use of predators to control pest populations?

(A) If the use of predators to control cyclamen mite populations fails, then parathion should be used to control these populations. X
(B) Until the effects of the predators on beneficial insects that live in strawberry fields are assessed, such predators should be used with caution to control cyclamen mite populations. X
(C) Insecticides should be used to control certain pest populations in fields of crops only if the use of natural predators has proven inadequate. x
(D) If an insecticide can effectively control pest populations as well as predator populations, then it should be used instead of predators to control pest populations. X
(E) Predators generally control pest populations more effectively than pesticides because they do not harm the crops that their prey feed on. X

Paragraph 3 says the following, verbatim:
"One group of strawberryplants was stocked with both predator and prey mites, a second group was kept predator-free by regularapplication of parathion, an insecticide that kills the predatory species but does not affect the cyclamen mite."

Simply, the insecticide parathion doesn't work against the cyclamen mite. Why should we resort to using insecticides? In fact, the answer to A RULES OUT C - A is wrongly precisely because of the fact that parathion is ineffective against these mites.

The whole point of the passage is that Typha mites are the last effective means...so if insecticides (according to C) can be used, then what's the point of focusing on the Typha mites?

This is a silly answer to me.
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Suppose that pesticide X drastically slows the reproductive rate of cyclamen mites and has no other direct effect on cyclamen mites or Typhlodromus. Based on the information in the passage, which one of the following would most likely have occurred if, in the experiments mentioned in the passage, pesticide X had been used instead of parathion, with all other conditions affecting the experiments remaining the same?

(A) In both treated and untreated plots inhabited by both Typhlodromus and cyclamen mites, the latter would have been effectively controlled.
(B) Cyclamen mite populations in all treated plots from which Typhlodromus was absent would have been substantially lower than in untreated plots inhabited by both kinds of mites.
(C) In the treated plots, slowed reproduction in cyclamen mites would have led to a loss of reproductive synchrony between Typhlodromus and cyclamen mites.
(D) In the treated plots, Typhlodromus populations would have decreased temporarily and would have eventually increased.
(E) In the treated plots, cyclamen mite populations would have reached significantly damaging levels more slowly, but would have remained at those levels longer, than in untreated plots.

Anyone please explain question 4.
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Can someone please explain Q7 ? I am not able to understand it.

Also with Q8, why is A correct ? I picked D because I couldn't find much for A.
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Can someone please explain Q7 ? I am not able to understand it.

Also with Q8, why is A correct ? I picked D because I couldn't find much for A.

Explanation

7. Which one of the following would, if true, most strengthen the author’s position regarding the practical applicability of the information about predatory mites presented in the passage?

Difficulty Level: 600

Explanation

The author concludes that predatory control can be effective because of the predator’s ability to adapt its population to its prey’s population. However, for this argument to work, the author has to assume that there’s no practical factor that would negate the predator’s ability to do so in the real world. So, to strengthen this argument, we want to show that there’s nothing that negatively affects the Typhlodromus mite’s ability to survive and control cyclamen.

(A) A correlation between life span and the number of eggs is irrelevant to the argument.

(B) Opposite. If the insecticides also killed the prey, then there would be no need for the predators to keep prey in check.

(C) According to the passage, winter is when cyclamen numbers dwindle and the Typhlodromus mites subsist on honeydew. The passage says nothing to indicate whether the winters in question are short and mild or long and frigid. So this doesn’t help the argument.

(D) Irrelevant. Other species and insecticides are not factors in the application of predators to crop control.

(E) One thing that could affect the Typhlodromus mite’s usefulness would be an inability to live in the environment where most strawberry plants grow. By saying that Typhlodromus mites can tolerate the same climate as strawberry plants, (E) rules out a potential weakener, thereby strengthening the argument. This is the correct answer.

Answer: E

8. Information in the passage most strongly supports which one of the following statements?

Difficulty Level: 700-750

Explanation

Since there are no clues in the question stem, we need to check the answers one at a time remembering the overall topic, scope, purpose, and main idea.

(A) The passage suggests that allowing Typhlodromus to thrive can be an effective solution to strawberry pests. No agricultural technique that destroyed the crop it was intended to help would be much of a solution. So, this is the correct answer.

(B) Extreme. Cyclamen and Typhlodromus mites happen to have the same mode of reproduction, but the author does not go so far as to say that this is a reason for (let alone crucial to) the effectiveness of the control.

(C) Other strawberry plant pests are Out of Scope.

(D) Opposite. According to Paragraph 1, cyclamens don’t reach damaging levels until the second year.

(E) The implied causality here is Out of Scope. We don’t know what actual strawberry growers have tried; we only have data from the greenhouse and field experiments.

Answer: A
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in question 5..why is c the answer and not e?
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suhanisinghal
in question 5..why is c the answer and not e?

(C) A little formal logic here in the Reading Comp section. Translating, this says that if you use insecticides, then natural predators should be proven inadequate. The contrapositive says that if natural predators are adequate to control pest population, you shouldn’t need insecticides. And this fits the author’s opinions perfectly. This is the answer.

(E) Tempting, but we don’t know if the predators have any effect on the crops. That’s never mentioned in the passage, so this is Out of Scope.
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Hi jrk23

Please find below:

Suppose that pesticide X drastically slows the reproductive rate of cyclamen mites and has no other direct effect on cyclamen mites or Typhlodromus. Based on the information in the passage, which one of the following would most likely have occurred if, in the experiments mentioned in the passage, pesticide X had been used instead of parathion, with all other conditions affecting the experiments remaining the same?

From the passage above, we know that cyclamen mites(CM)'s reproductivity will be reduced drastically. Suppose In first year 100 CM infest the plot. By second year they were supposed to reach to level of 1000, but could not and remained at more or less at that level due to pesticide X. Now Typhlodromus(T) infests the plot in second year. They will reproduce according to the population level of CM. now that CM are at level of 100, T will also maintain their population in tandem to them. Let us say T grows to 150. Now this relation can be maintained till the effect of pesticide lasts.

(A) In both treated and untreated plots inhabited by both Typhlodromus and cyclamen mites, the latter would have been effectively controlled. -->Correct. In this option latter refers to CM and not untreated plots. Now when you will think this will make sense. In untreated plot we were anyways able to control the pest with the help of predators, but with treating the plot we are able to maintain as explained in the above case.
(B) Cyclamen mite populations in all treated plots from which Typhlodromus was absent would have been substantially lower than in untreated plots inhabited by both kinds of mites. -> Incorrect. We cannot infer this. For all we know it could be same in both types of plots. In treated population of pests is maintained at level of 100, as explained in the example and in untreated plot, predators reduced the population of pest to 100 by excessive predation.
(C) In the treated plots, slowed reproduction in cyclamen mites would have led to a loss of reproductive synchrony between Typhlodromus and cyclamen mites. -> Incorrect. This population is about loss of synchrony which might not be the case. For all we know they might be able to maintain synchrony at very lower levels also.
(D) In the treated plots, Typhlodromus populations would have decreased temporarily and would have eventually increased.->Incorrect. Again this can not be inferred. All we know that their population will grow too much due to the level of population down in CM. But we cannot infer that their population will decrease, and will get chance to increase.
(E) In the treated plots, cyclamen mite populations would have reached significantly damaging levels more slowly, but would have remained at those levels longer, than in untreated plots. ->Incorrect. Can we can not say with certainty. For all we know, in untreated plots also the population of prey could have reduced to damaging low level due to predation and remained at the level due to synchrony.
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HI AnirudhaS VeritasKarishma,

Shouldn't the answer to Q2 be A , which can be inferred from the line
Seasonal synchrony of Typhlodromus reproduction with the
growth of prey populations and ability to survive at
low prey densities also contribute to the predatory
efficiency of Typhlodromus.
In option D , relation between consumption level and population of prey is stated which can be inferred from increasing reproduction in predators .SO I think most direct answer should be A.
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HI AnirudhaS VeritasKarishma,

Shouldn't the answer to Q2 be A , which can be inferred from the line
Seasonal synchrony of Typhlodromus reproduction with the
growth of prey populations and ability to survive at
low prey densities also contribute to the predatory
efficiency of Typhlodromus.
In option D , relation between consumption level and population of prey is stated which can be inferred from increasing reproduction in predators .SO I think most direct answer should be A.

(A) is the trap answer here.

2. Based on the passage, the author would probably hold that which one of the following principles is fundamental to long-term predatory control of agricultural pests?

(A) The reproduction of the predator population should be synchronized with that of the prey population, so that the number of predators surges just prior to a surge in prey numbers.

"synchronized" is correct but the use of the words "just prior" is not. The author doest not say or imply that the predator population should respond before the prey population surge. She just says that the two population sizes should be synchronised.

"Its population can increase as rapidly as that of its
prey."
"Seasonal
synchrony of Typhlodromus reproduction with the
(25) growth of prey populations and ability to survive at
low prey densities also contribute to the predatory
efficiency of Typhlodromus."



(D) The predator population’s level of consumption of the prey species should be responsive to variations in the size of the prey population.

From above, we know that predator population should respond to changes in prey population. So this is correct.

Answer (D)
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Hello Sajjad1994 can you help in providing the OE of Question 4?
Thanks.
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Hello Sajjad1994 can you help in providing the OE of Question 4?
Thanks.

Explanation

4. Suppose that pesticide X drastically slows the reproductive rate of cyclamen mites and has no other direct effect on cyclamen mites or Typhlodromus. Based on the information in the passage, which one of the following would most likely have occurred if, in the experiments mentioned in the passage, pesticide X had been used instead of parathion, with all other conditions affecting the experiments remaining the same?

Difficulty Level: 750-800

Explanation

For this question, we have to revisit the experiments mentioned in the passage. Both experiments included one plot treated with pesticide and one without. The one with pesticide killed the predators, leading to dangerous levels of cyclamen mites. The one without saw cyclamen population kept in check by the predators.

This time, the question wants us to consider a different pesticide—one that doesn’t affect the predator but instead slows the reproduction of the cyclamen mites. In that case, based on the details of the second paragraph, the Typhlodromus mites should be able to adjust its population to the new, slower reproducing cyclamen. So with the new pesticide, the cyclamen’s population should be kept in check. And since the untreated plot doesn’t change, we would experience controlled pest populations in both cases. That’s what answer choice (A) says.

(B) If the Typhlodromus mites were absent, there would be no predators to eat the cyclamen mites. So, even if pesticide slowed cyclamen reproduction, there would still be no predators to keep the population in check and, in that case, it is likely that the cyclamen population would ultimately be higher, not lower.

(C) The way seasonal synchrony is described in Paragraph 2, the slowed reproduction would have no effect on Typhlodromus mites. Typhlodromus mites would still be able to reproduce faster should the cyclamen population increase. And with slowed reproduction, the Typhlodromus mites should still be able to subsist on honeydew during times of dwindled cyclamen population.

(D) With a slower reproduction rate for cyclamen, it might make sense that Typhlodromus populations would decrease initially. But, according to Paragraph 2, Typhlodromus mites only reproduce when they’re feeding on cyclamen mites. If the cyclamen reproduction is slowed, there’s no reason to expect the Typhlodromus mites to increase again after decreasing to match the cyclamen.

(E) Again, with a slower reproduction rate for cyclamen, it makes sense that damaging population levels would take longer to achieve. However, nothing suggests this dangerous level would last any longer than if reproduction rate was normal. In either case, the damaging level might last only until they’d eaten up all the strawberries.

Answer: A

PS: As this is an LSAT passage one might not see such a hard and LSAT-only question in the real GMAT.

Cheers
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Can someone explain why the answer can't be E for question 5?
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sumona0607
Can someone explain why the answer can't be E for question 5?
Explained here: https://gmatclub.com/forum/sometimes-th ... l#p2819594
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Question 2:
Based on the passage, the author would probably hold that which one of the following principles is fundamental to long-term predatory control of agricultural pests?

Correct Ans:
(D) The predator population's level of consumption of the prey species should be responsive to variations in the size of the prey population.
This principle is shown in the passage through how Typhlodromus effectively controls cyclamen mite populations. Specifically:

  1. The passage notes in lines 24-27 that "Seasonal synchrony of Typhlodromus reproduction with the growth of prey populations and ability to survive at low prey densities also contribute to the predatory efficiency of Typhlodromus."
  2. Lines 32-34 state that the predatory mites "do not reproduce except when they are feeding on the cyclamen mites," showing how their reproduction is directly tied to prey consumption.
  3. Lines 57-60 describe how "When cyclamen mite populations began to increase in an untreated planting, the predator populations quickly responded to reduce the outbreak," demonstrating the responsiveness that makes predator control effective.

Reasons to eliminate other options:
(A) The reproduction of the predator population should be synchronized with that of the prey population, so that the number of predators surges just prior to a surge in prey numbers.
  • The passage indicates synchrony is important (lines 24-27), but it doesn't state predators should surge "prior to" prey numbers increasing. Instead, it shows predators responding to increases in prey.
  • Lines 57-60 explicitly state that "when cyclamen mite populations began to increase...the predator populations quickly responded," indicating the response follows the increase, not precedes it.
(B) The effectiveness of the predatory relationship should be experimentally demonstrable in greenhouse as well as field applications.
  • This describes a scientific validation method, not a principle of predatory control itself.
  • The passage mentions experiments to verify effectiveness, but doesn't suggest demonstrability is fundamental to the control mechanism.
(C) The prey population should be able to survive in times of low crop productivity, so that the predator population will not decrease to very low levels.
  • This reverses the relationship described in the passage.
  • The passage emphasizes the predator's ability to survive when prey populations are low (lines 25-32), not the other way around.
(E) The predator population should be vulnerable only to pesticides to which the prey population is also vulnerable.
  • Contradicted by the passage, which specifically notes parathion "kills the predatory species but does not affect the cyclamen mite" (lines 43-45).
  • The passage actually uses this differential vulnerability to demonstrate why pesticide use is harmful.

Question 5:
5. It can be inferred from the passage that the author would be most likely to agree with which one of the following statements about the use of predators to control pest populations?

Correct Ans:
(C) Insecticides should be used to control certain pest populations in fields of crops only if the use of natural predators has proven inadequate.
The passage strongly advocates for using natural predators (Typhlodromus mites) over insecticides (parathion) for controlling cyclamen mite populations. The author explicitly states in lines 50-52: "Applying parathion in this instance is a clear case in which using a pesticide would do far more harm than good to an agricultural enterprise."


The author demonstrates through experiments that natural predation is highly effective, with cyclamen mites being "about 25 times more abundant in the absence of predators than in their presence" (lines 59-60). The entire passage builds a case for the effectiveness of natural predation as the preferred control method.


Option C aligns with this position by suggesting insecticides should be used only as a fallback when natural predation proves inadequate - which matches the author's preference for natural solutions first.



Reasons to eliminate other options:
(A) If the use of predators to control cyclamen mite populations fails, then parathion should be used to control these populations.
  • The passage specifically argues against using parathion, calling it a "clear case in which using a pesticide would do far more harm than good" (lines 50-52).
  • There's no suggestion that parathion would be appropriate even if predator control failed.
(B) Until the effects of the predators on beneficial insects that live in strawberry fields are assessed, such predators should be used with caution to control cyclamen mite populations.
  • The passage doesn't mention concerns about effects on other beneficial insects.
  • The author presents predator control as clearly beneficial without expressing caution.
(D) If an insecticide can effectively control pest populations as well as predator populations, then it should be used instead of predators to control pest populations.
  • Directly contradicts the author's position, which strongly favors natural predation over insecticides.
  • The passage shows that parathion did control both populations but resulted in worse outcomes.
(E) Predators generally control pest populations more effectively than pesticides because they do not harm the crops that their prey feed on.
  • While the passage shows predators are more effective, it doesn't attribute this to predators not harming crops.
  • The effectiveness is attributed to factors like reproductive capabilities, seasonal synchrony, and ability to survive at low prey densities.

Question 8:
Information in the passage most strongly supports which one of the following statements?

[color=#17b529]Correct Ans: [/color]
(A) Strawberry crops can support populations of both cyclamen mites and Typhlodromus mites without significant damage to those crops.
This statement is strongly supported by the passage, which shows that when both species coexist, the strawberry crops remain healthy. Key evidence includes:

  • Lines 42-49 describe an experiment where plants with both predator and prey mites had low cyclamen mite populations and avoided significant damage, while predator-free plants suffered "significantly damaging proportions" of infestation.
  • Lines 52-56 confirm similar results in field plantings, where cyclamen mites reached damaging levels when predators were eliminated but "did not attain such levels in untreated plots" (where both species coexisted).
  • The overall data showed cyclamen mites were "about 25 times more abundant in the absence of predators than in their presence" (lines 59-60), indicating that strawberry crops can indeed support both species without significant damage when the natural predator-prey relationship is maintained.

Reasons to eliminate other options:
[b](B) For control of cyclamen mites by another mite species to be effective, it is crucial that the two species have the same mode of reproduction.
[/b]
  • While the passage mentions both species reproduce by parthenogenesis (lines 18-20), it doesn't state this similarity is crucial for effective control.
  • The passage attributes effectiveness to other factors like voracious appetite, rapid population growth, seasonal synchrony, and survival ability at low prey densities.
[b](C) Factors that make Typhlodromus effective against cyclamen mites also make it effective against certain other pests of strawberry plants.[/b]
  • The passage doesn't mention Typhlodromus controlling any pests other than cyclamen mites.
  • While it mentions Typhlodromus consuming honeydew from aphids and white flies during winter, it doesn't indicate this controls those insects.
[b](D) When Typhlodromus is relied on to control cyclamen mites in strawberry crops, pesticides may be necessary to prevent significant damage during the first year.[/b]
  • Contradicted by the passage, which states cyclamen mites "typically establish themselves in a strawberry field shortly after planting, but their populations do not reach significantly damaging levels until the plants' second year" (lines 7-10).
  • This suggests pesticides aren't necessary in the first year since damage isn't significant then.
[b](E) Strawberry growers have unintentionally caused cyclamen mites to become a serious crop pest by the indiscriminate use of parathion.[/b]
  • Not supported by the passage, which only discusses parathion in controlled experiments.
  • The passage presents cyclamen mites as an existing pest problem, not one created by pesticide use.
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