Q13 - Adult frogs are vulnerable to

[ohthatpatrick]

Question Type:
Inference (most supported)

Stimulus Breakdown:
CAUSALITY: highly permeable skin makes adult frogs vulnerable to dehydration.
CONTRAST: Large AF's can survive in arid (dry) climates, but small AF's can't (their low ratio of body weight to skin surface is the CAUSE).
CAUSALITY: The AF's moisture requirements are the #1 factor determining where they can live.
CONTRAST: North Yucatan is arid; south is wet.

Answer Anticipation:
Inference questions want us to combine facts, usually using Conditional / Causal / Contrast / Quantitative language. Here it looks like the 2nd and 3rd sentence interact well. They are both about where adult frogs can live. Since large frogs CAN live in arid climates but small frogs can't, it looks like large frogs can live in the north and the south of the yucatan, while the small frogs could only live in the wetter south. There's no great way to link in the first sentence, since it's about adult frogs in general (large and small combined). So they're probably just looking for what sentence 2 and 3 together tell us about where large vs. small frogs can live in the Yucatan.

Correct Answer:
C

Answer Choice Analysis:
(A) Extreme: "cannot coexist"? Where did we get the idea they can't live together?

(B) New Comparison/Opposite: we can't compare body weight in these different areas. Even if we COULD, we know arid has ONLY large frogs, while wet would have large and small. Thus, we would actually assume that the average weight in an arid area would be higher (since it's nothing but large frogs).

(C) True that! Since small adults can't live in arid climates, they can't live in the north.

(D) New Comparison: we can't compare the quantity of large vs. small in the south. We could compare it in the north! (some vs. none)

(E) Opposite: there are no small adults in the north. And you can't be less than zero.

Takeaway/Pattern: The correct answer to Inference doesn't have to magically tie all the ideas together (that's what E is hoping to trap us into thinking). But it WILL almost always involve combining two or more ideas together. Look for distinctions ("unlike large adult frogs, small adult frogs ..."), causality ("vulnerable because of " .."the most important factor determining .."), and overlapping ideas ("arid climates"). When two sentences involve some overlapping element, you can usually infer something.

#officialexplanation

[jennifer]

I am having some difficulty in understanding why C is correct. Is it correct because the passage gives no restrictions/negative concequences of large adult frogs, thus the area in which they live is not limited vs. the small adult frogs who can not live in arid climates?

[cyruswhittaker]

The question asks which of the choice is "most strongly" supported.

I found that this problem was a good one to work through by POE:

Choices/Explanations:

A) Incorrect: The information does not provide enough to determine anything about the two frog types coexisting together.

B) Incorrect: This is unsupported. All we can say is that the small adult frogs cannot survive in arid climates due to the ratio of weight/skin surface area. This answer choice seems to even be contradictory to the information, since it would seem that more small frogs would live in the wet areas than in the arid areas, thus potentially driving the average weight down.

C) Correct: The passage states that the moisture requirements is the "most important factor" in determining where the frogs can live. So if the small frogs can't live in the North (arid) but the large frogs can, then this is supported. Notice that this choice isn't COMPLETELY supported without question (i.e. not a Must Be True answer), but it's the best out of the choices.

D) Incorrect: We don't have enough information to form a quantitative comparison between the number of small/large frogs in the wet areas.

E) Incorrect: We don't have enough info to determine that the skin permeability actually changes in the frogs depending on the location.

[bbirdwell]

Here's how I look at it.

1. Moisture requirement = most important factor
2. small frogs cannot live in arid climates
3. large frogs can ("Unlike large frogs, small frogs cannot...")
4. Yucatan = arid in the north, wet in the south

Now put it all together.
Though not 100% provable, as Cyrus pointed out, it is reasonable to infer that Large frogs can live in the north or the south, while small frogs can only live in the south.

Large frogs = both. Small frogs = 1 area only.

(C)

[cyruswhittaker]

Here's how I look at it.

1. Moisture requirement = most important factor
2. small frogs cannot live in arid climates
3. large frogs can ("Unlike large frogs, small frogs cannot...")
4. Yucatan = arid in the north, wet in the south

Now put it all together.
Though not 100% provable, as Cyrus pointed out, it is reasonable to infer that Large frogs can live in the north or the south, while small frogs can only live in the south.

Large frogs = both. Small frogs = 1 area only.

(C)

The challenge with the LR portion of the LSAT, for me at least, is knowing when we go by a more "comprehensive" look at the question and when we need to really be nit-picky about each word..

[redcobra21]

I recognize that this is a "most strongly supported" question, but how in the world can you conclude anything like (C) without knowing more information about the large adult frogs? The stimulus gives you information about how small frogs cannot live in the north, but there is nothing abut large adult frogs. It could be equally plausible that the the large frogs cannot survive in wet climates for opposite reasons (i.e. high ratio of body weight to skin means you cannot survive in non-arid climates), or that there is some other reason why large frogs cannot survive in arid climates. There simply is not enough information to know.

I think what the previous posters are missing regarding the question stem is the part where it says which one most strongly supports a following conclusion. How can you make a conclusion about large adult frogs when you only know about small frogs? Or should we just be writing off this portion of the question?

Thanks

[ohthatpatrick]

I certainly understand your qualms, and I'm pretty sure that no matter what I say you're still going to have them.

First of all, "conclusions" is not as big a deal as you're making it out to be. A conclusion is just a claim derived from some supporting idea(s). Calling something a conclusion doesn't imply that it is a logically valid one. So calling these answer choices "conclusions" does not mean we hold them to the standard of "absolutely proven".

Secondly, it's not true that we know NOTHING about large adults. We know, via the "unlike large adult frogs", that they DON'T have a weight/skin ratio that precludes them from arid climates. (As you said, something else might preclude them from arid climates or something else might preclude them from moist climates).

However, the first sentence says that adult frogs are vulnerable to dehydration. So it seems somewhat against the grain to speculate that frogs might be troubled by a wet climate.

Finally, they give us a sentence saying that "moisture requirements" is the MOST important factor determining possible habitats.

Again, that doesn't preclude the possibility that some less important factor could still be a dealbreaker.

But it again makes it more against the grain for us to speculate about such possibilities.

At the beginning of every LR section, there's a line from LSAT that we should not make any assumptions that are by commonsense standards implausible, superfluous, or incompatible with the stimulus. So the idea that large adult frogs have a weight/skin ratio that would keep them from living in wet climates is borderline incompatible (because of the 'vulnerable to dehydration' line) and the idea that there is some other quality of large adults we don't know about is borderline superfluous (because of the 'most important factor' line).

The wiggle room ideas you were pointing to are definitely legit (i.e. choice C is by NO means PROVEN by the facts provided), but in terms of playing the game the test is playing, we're asked in Q13 for the most supportable answer, and (C) definitely wins by that standard.

Hope this helps you sleep at night.

[contropositive]

when I read "more of the area" i thought of it in terms of size and I was thinking "how is north bigger than south" now I get it...grrrr

[stacksdoe]

redcobra21: I'm going to picky-back of Patrick. As he said, I can say all of what you say is true or invalid, but I will say what argue may indeed be true; and in fact, I actually had similar questions during my thinking process, especially when I was evaluating answer choice (c). However, upon my most recent observation, I realized one word changes a lot: can. Notice that answer (c) simply states - using the information pointed out about Adult frogs that the stimulus gives us, and contrary what you state, that we don't know anything about adult frog, we know two things, and Patrick covered them - that Adult frogs CAN live in more areas then the small adult frogs of the Peninsula. If you confused CAN with DOES that that would be very problematic, for those exact same points you stated. However, can only means it's a possibility and not that it is the case. So answer choice (C) is toying with the notion of conditional reasoning, its's not necessarily true that this adult frogs cover more space - both north and south - it just that it is possible/plausible. I looked it this way, the adult frogs can roam/cover in more area/space of the YP then the small adult frogs and this is certainly a FACT as outlined by the stimulus. Hopefully I made some sense and didn't confuse you more!!!