Q21

[didi0504]

Please explain A and D~

thanks!

[noah]

I see support for (D) - lines 33 - 37 (and the general gist of that entire paragraph).

What's your support for (B)? Yes, the passage does mention a greenhouse experiment that shows a predatory relationship can work to control pests, but does the passage indicate that the predatory relationship must be provable in a greenhouse? It's nice that it was in this instance, but nobody is suggesting that it always must be.

Does that clear it up?

[irene122]

Hi Noah, could you explain why A incorrect? I find it quite supported in paragraph 2.

Thanks in advance!

[goriano]

Hi Noah, could you explain why A incorrect? I find it quite supported in paragraph 2.

Thanks in advance!

I eliminated (A) because the passage states in line 32 "they do not reproduce EXCEPT WHEN they are feeding on the cyclamen mites." Presumably that means IF they reproduce, THEN they are feeding on cyclamen mites, which suggests that the number of predators would surge AFTER a surge in prey numbers.

Could someone confirm/disconfirm this line of reasoning?

[mlbrandow]

There are at least two areas of the passage which conflict with answer choice (A):

Lines 10-14 suggest that the predator population can effectively control the prey population by surging after the prey reaches significantly damaging levels. (Line 15 credits this as "effective.")

Further, lines 56-59 state that the predator population can "quickly respond," suggesting its population increases at some time after the prey population.

The key to (A) being incorrect is the "just prior." If "prior" is replaced with "after," it would be correct.

And, in fact, (D) essentially says just that.

[ManhattanPrepLSAT1]

Nice discussion. You've got it!

Answer choice (A) should not have said that the predator population should surge just prior to a surge in prey numbers, since the author clearly says that a surge just after is effective (line 15).

[T.J.]

Hey people, you guys are making this question harder than it should be. First, if you contemplate on what the word "fundamental" really means, you would know that it resembles the meaning of "necessary". Within the context of this question, it asks us which one of the following, if not included, would make long-term control of the pests a failure. Then you'll find that this goal could be reached with the negation of every single choice except D. For D, if the predator's consumption isn't responsive, then the pest would prevail in the field, leading to a disaster. If so, the predator becomes useless. In conclusion, D is fundamental to the long-term success to pest control.
The justification of my thinking is the recent trend in which RC questions got a hint of what LR questions are like.

[tommywallach]

Hey T.J.,

Your explanation is absolutely right, BUT part of the process of improving on the LSAT is to really focus in on why the wrong answers are wrong, as opposed to just why the right answers are right. In other words, it's great if you zeroed in on (D), but it isn't "making things too complicated" to discuss why the wrong answers are wrong. That's how we get better!

-t

[MayaM405]

Hi everyone,

Can someone explain why C is incorrect? I found support for C in lines 23-27. I know low crop activity isn't specifically supported but this seemed like a reasonable jump from the discussion of winter especially since the lines above refer to seasonal synchrony.

Thanks!

[ohthatpatrick]

(sorry for the late response; this slipped through the cracks)

Let's remind ourselves that here
predator = Typhlodromus
prey = cyclamen

(C) is saying that "It was important that cyclamen mites survived in times of low crop productivity".

As you said, can we find anything like that in the passage? If not, we wouldn't want to pick it. All of our selected answers should be paired up with whatever supporting text we think we have to justify it.

Lines 23-27 were saying "It was important that Typhlodromus was able to survive in times of low cyclamen density".

Meanwhile, the correct answer (D) is saying "it was important that Typhlodromus's level of eating cyclamen was responsive to variations in the size of the cyclamen population".

Line 17-18 supports that T was able to reproduce enough (responsive) to keep up with rapidly growing C populations.

Lines 23-32 are saying T was able to stop eating C's (and stop reproducing) when C populations shrunk.

Hope this helps.