Long after the lava has cooled, the effects of a major volcanic

Question

Long after the lava has cooled, the effects of a
major volcanic eruption may linger on. In the
atmosphere a veil of fine dust and sulfuric acid droplets
can spread around the globe and persist for years.
 (5)  Researchers have generally thought that this veil can
block enough sunlight to have a chilling influence on
Earth’s climate. Many blame the cataclysmic eruption
of the Indonesian volcano Tambora in 1815 for the
ensuing “year without a summer” of 1816—when parts
 (10)  of the northeastern United States and southeastern
Canada were hit by snowstorms in June and frosts in
August.

The volcano-climate connection seems plausible,
but, say scientists Clifford Mass and Davit Portman, it
 (15)  is not as strong as previously believed. Mass and
Portman analyzed global temperature data for the years
before and after nine volcanic eruptions, from Krakatau
in 1883 to El Chichón in 1982. In the process they tried
to filter out temperature changes caused by the cyclic
 (20)  weather phenomenon known as the El Niño-Southern
Oscillation, which warms the sea surface in the
equatorial Pacific and thereby warms the atmosphere.
Such warming can mask the cooling brought about by
an eruption, but it can also mimic volcanic cooling if
 (25)  the volcano happens to erupt just as an El Niño
induced warm period is beginning to fade.
Once El Niño effects had been subtracted from the
data, the actual effects of the eruptions came through
more clearly. Contrary to what earlier studies had
 (30)  suggested, Mass and Portman found that minor
eruptions have no discernible effect on temperature.
And major, dust-spitting explosions, such as Krakatau
or El Chichón, cause a smaller drop than expected in
the average temperature in the hemisphere (Northern or
 (35)  Southern) of the eruption—only half a degree
centigrade or less—a correspondingly smaller
drop in the opposite hemisphere.

Other researchers, however, have argued that even
a small temperature drop could result in a significant
 (40)  regional fluctuation in climate if its effects were
amplified by climatic feedback loops. For example, a
small temperature drop in the northeastern U.S. and
southeastern Canada in early spring might delay the
melting of snow, and the unmelted snow would
 (45)  continue to reflect sunlight away from the surface,
amplifying the cooling. The cool air over the region
could, in turn, affect the jet stream. The jet stream
tends to flow at the boundary between cool northern air
and warm southern air, drawing its power from the
 (50)  sharp temperature contrast and the consequent
difference in pressure. An unusual cooling in the region
could cause the stream to wander farther south than
normal, allowing more polar air to come in behind it
and deepen the region’s cold snap. Through such a
 (55)  series of feedbacks a small temperature drop could be
blown up into a year without a summer.   
 1 
 1. Which one of the following most accurately expresses the main idea of the passage?

(A) The effect of volcanic eruptions on regional temperature is greater than it was once thought to be.
(B) The effect of volcanic eruptions on regional temperature is smaller than the effect of volcanic eruptions on global temperature.
(C) The effect of volcanic eruptions on global temperature appears to be greater than was previously supposed.
(D) Volcanic eruptions appear not to have the significant effect on global temperature they were once thought to have but might have a significant effect on regional temperature.
(E) Researchers tended to overestimate the influence of volcanic eruptions on global temperature because they exaggerated the effect of cyclical weather phenomena in making their calculations.

2 
 2. Not taking the effects of El Niño into account when figuring the effect of volcanic eruptions on Earth’s climate is most closely analogous to not taking into account the

(A) weight of a package as a whole when determining the weight of its contents apart from the packing material
(B) monetary value of the coins in a pile when counting the number of coins in the pile
(C) magnification of a lens when determining the shape of an object seen through the lens
(D) number of false crime reports in a city when figuring the average annual number of crimes committed in that city
(E) ages of new immigrants to a country before attributing a change in the average of the country’s population to a change in the number of births

3 
 3. The passage indicates that each of the following can be an effect of the El Niño phenomenon EXCEPT:

(A) making the cooling effect of a volcanic eruption appear to be more pronounced than it actually is
(B) making the cooling effect of a volcanic eruption appear to be less pronounced than it actually is
(C) increasing atmospheric temperature through cyclic warming of equatorial waters
(D) initiating a feedback loop that masks cooling brought about by an eruption
(E) confounding the evidence for a volcano climate connection

4 
 4. Which one of the following most accurately characterizes what the author of the passage means by a “minor” volcanic eruption (line 30)?

(A) an eruption that produces less lava than either Krakatau or El Chichón did
(B) an eruption that has less of an effect on global temperature than either Krakatau or El Chichón did
(C) an eruption whose effect on regional temperature can be masked by conditions in the hemisphere of the eruption
(D) an eruption that introduces a relatively small amount of debris into the atmosphere
(E) an eruption that causes average temperature in the hemisphere of the eruption to drop by less than half a degree centigrade

5 
 5. To which one of the following situations would the concept of a feedback loop, as it is employed in the passage, be most accurately applied?

(A) An increase in the amount of decaying matter in the soil increases the amount of nutrients in the soil, which increases the number of plants, which further increases the amount of decaying matter in the soil.
(B) An increase in the number of wolves in an area decreases the number of deer, which decreases the grazing of shrubs, which increases the amount of food available for other animals, which increases the number of other animals in the area.
(C) An increase in the amount of rain in an area increases the deterioration of the forest floor, which makes it harder for wolves to prey on deer, which increases the number of deer, which gives wolves more opportunities to prey upon deer.
(D) An increase in the amount of sunlight on the ocean increases the ocean temperature, which increases the number of phytoplankton in the ocean, which decreases the ocean temperature by blocking sunlight.
(E) As increase in the number of outdoor electric lights in an area increases the number of insects in the area, which increases the number of bats in the area, which decreases the number of insects in the area, which decreases the number of bats in the area.

6 
 6. The author of the passage would be most likely to agree with which one of the following hypotheses?

(A) Major volcanic eruptions sometimes cause average temperature in the hemisphere of the eruption to drop by more than a degree centigrade.
(B) Major volcanic eruptions can induce the El Niño phenomenon when it otherwise might not occur.
(C) Major volcanic eruptions do not directly cause unusually cold summers.
(D) The climatic effects of minor volcanic eruptions differ from those of major eruptions only in degree.
(E) El Niño has no discernible effect on average hemispheric temperature.

7 
 7. The information in the passage provides the LEAST support for which one of the following claims?

(A) Major volcanic eruptions have a discernible effect on global temperature.
(B) The effect of major volcanic eruptions on global temperature is smaller than was previously thought.
(C) Major volcanic eruptions have no discernible effect on regional temperature.
(D) Minor volcanic eruptions have no discernible effect on temperature in the hemisphere in which they occur.
(E) Minor volcanic eruptions have no discernible effect on temperature in the hemisphere opposite the hemisphere of the eruption.

8 
 8. The primary purpose of the last paragraph of the passage is to

(A) describe how the “year without a summer” differs from other examples of climatic feedback loops
(B) account for the relatively slight hemispheric cooling effect of a major volcanic eruption
(C) explain how regional climatic conditions can be significantly affected by a small drop in temperature
(D) indicate how researchers are sometimes led to overlook the effects of El Niño on regional temperature
(E) suggest a modification to the current model of how feedback loops produce changes in regional temperature

Sajjad1994 · Answer

Explanation

3. The passage indicates that each of the following can be an effect of the El Niño phenomenon EXCEPT:

Explanation

The important thing here is that you restrict your analysis to  Paragraph 2  and the early part of  Paragraph 3 , the only places in which El Niño comes into play. From  lines 18-29  we basically get four facts about El Niño, and not coincidentally, those four facts have been turned into the four wrong choices.

Lines 18-22  say that El Niño warms the surface of the Pacific and hence— choice (C) — "warms the atmosphere."   Paragraph 2  continues by noting that an El Niño can  “mask the cooling brought about by”  a volcano erupting —that’s  (B) ; and then it says that, conversely, an El Niño can  “mimic...cooling,”  i.e. can make things seem cooler than they really are. That’s  (A) .

As a result, says  Paragraph 3 , by eliminating El Niño from the calculations you can get a truer picture, one that gets to the heart of the volcano-climate connection. That’s  (E) .

(D)  is perhaps hard to fix upon because its use of the phrase  “masks cooling”  conjures up a point  (line 23)  that is in the midst of the El Niño discussion. But the whole concept of  “feedback loops”  doesn’t arise until two paragraph’s later!  Paragraph 4  is about a whole different kind of relationship between volcanoes and climate, and by then we’ve left all consideration of El Niño far behind. If you chose  (D)  as an effect of El Niño you were working too hard to see a  “feedback loop”  at work in  lines 18-29 . The author doesn’t use the phrase in that specific context, so why should we?

Answer: D

4. Which one of the following most accurately characterizes what the author of the passage means by a “minor” volcanic eruption (line 30)?

Explanation

“Minor eruptions”  are polished off briskly, both by Mass & Portman and by the author. When you discount the effects of El Niño, says  lines 30-32, “minor eruptions have no discernible effect on temperature. And major, dust-spitting explosions,...” —that emphasis is ours, to highlight that the minor eruptions in question are used by the author to contrast with the big dust-spitters.  (D)  is a discreet paraphrase of  “minor dust-spitter.”

(A)  The issue ever since  line 3  has been dust, not lava. Remember sentence 1? The entire passage is concerned with what happens  “long after the lava has cooled.”

(B)  is a distortion that takes two issues, global temperature and the names of two major volcanic events, and merges them together unacceptably. To the author, an eruption is  “minor”  or  “major”  sheerly because of its dust quotient, and not because of its effect on temperature.  (B) ’s focus on Krakatau and El Chichón is too narrow and misses the point.

(C), (E)  Minor eruptions  “have no discernible effect on temperature,”  so there’s nothing to mask,  (C) , and no drop in average hemispheric temperature is caused,  (E).

Answer: D

Explanation Credit: Kaplan LSAT

Sajjad1994 · Answer

Explanation

2. Not taking the effects of El Niño into account when figuring the effect of volcanic eruptions on Earth’s climate is most closely analogous to not taking into account the

Explanation

El Niño, you’ll recall, is a major weather phenomenon whose warming effect can either mask a volcanic eruption’s cooling, or mimic it  (lines 23-26) . Once El Niño’s effect is subtracted, the effect of a volcanic eruption on global climate is seen to be minimal. Not having subtracted El Niño, then—and that’s what the question asks us to consider—leads to a logical distortion. Doing so would be tantamount to ignoring a huge alternative explanation for certain climatic conditions, one that renders dubious indeed any conclusions drawn about volcanoes’ influence.

So an analogous situation will involve the failure to subtract some key factor that ought at least to be considered in drawing one’s conclusion. And this is what  (E)  presents. Before you decide that the change in a population’s average age must be due to a higher birth rate, better check out other plausible explanations—such as the one  (E)  suggests, the ages of new immigrants to the country. Maybe so many of them are old or young that that is what caused the higher average age; maybe the birth rate is really stable (just as volcanic eruptions are really negligible in terms of climatic change). Ignoring those immigrants would be like ignoring El Niño—turning a blind eye to an alternative explanation.

(A)  To not take into account  “the weight of the package as a whole”  when trying to determine the contents’ weight would be impossible—unless you were to remove the contents and weigh them separately, in which case the weight of the overall package would be of no interest to you. Either way,  (A)  isn’t a case of misleading data.

(B)  If your goal was to count the number of coins in a pile, it would be totally appropriate to not take into account the coins’ monetary value.

(C)  Without field-specific, technical knowledge uncalled-for by the LSAT, it is difficult to imagine how not taking into account lens magnification would affect the determination of an object’s shape. The shape is what it is; the magnification, inferably, might affect its size but not its shape.

(D)  goes wrong in that its goal is not to figure out the effect of some phenomenon (as in  (E)  and in the stimulus), but rather to make a straightforward computation.  (D)  would have been closer if it had evaluated whether something affects the crime rate.

Answer: E

Explanation Credit: Kaplan LSAT

yahya729 · Answer

Question 1 - main point.

Correct answer D. The author hasn't tried to argue whether the effects of volcanic eruptions are greater or not, but just presented sides. He also hasn't tried to compare variances in global vs regional, but just used those as examples to say that the effects could be large or small, so A, B and C are out. Finally E is completely out of scope as the main point isn't to criticize researchers.

Question 2 - impact of El-nino's analogy.

El-nino basically has an effect due to which the volcanic effect isn't as large. so to get an realistic analysis of the volcanic effect, we need to filter out Elnino's effect.

From the choices given, only E does something similar. you can't say that a countries population (in our case the temperate) has increased (decreased for us) because of more births. since immigrants (El-nino) have increased the population as well, the effects of more births (volcanic eruptions for us) is lesser than expected

Question 3 - effect of Elnino except.

Again, Elnino basically masks the volcanic effect. A,B and E say exactly that. C - warming of equatorial waters is mentioned. D is correct due to also process of elimination, but also because feedback loops are mentions in paragraph three which isn't related to Elnino

Question 4 - what are minor erupsions

reading on from line 30 "And major, dust-spitting explosions, such as Krakatau, or El Chichón"... thus a minor eruption is not a major dust-spitting explosion hence D

Question 5 - what is a feedback loop.

Tough question, moreso also because the answer choices are long. But what exactly is a feedback loop to start with? Something small which later on becomes something bigger due to domino effects in the middle. So all you're looking for is a small effect which leads to same effect later. only A answers that. decaying matter in soil leads to more decaying matter in soil. Wolves leading to animals is close, but A is the better option - the others aren't talking about the same effect

Question 6 - what hypothesis would the author not agree with

So from reading the passage we know that the author present 2 sorts of point of views and nothing extreme. for A, half a degree is mentioned, so this is out. B major eruptions don't induce elnino, they happen serpately. C is correct because the last paragraph is all about the feedback loop where things happens indirectly. D again mentions one degree which half a degree in the passage, and the difference is 0-0.5, and E is wrong also because passage 2 is all about how Elnino has an impact

Question 7 - least evidence for which of the following claims.

Okay, so the hardest question of the lot, moreso because you may also not know what discernable means. hence how do you eliminate A? is discernable big impact or a small impact? if its big, A is wrong, if its small, this could be right. so lets ignore this for now. 
B - major eruptions have a smaller impact. The 2nd passage is all about this. 
Aha - so what does B actually do? it actually answer A. Why would you have 2 options choices saying major eruptions have a smaller impact? so A must mean the volcanic eruptions have a big impact. so that was mentioned in passage 1, hence A is out also. 
And now you've figured out what discernable kind of means. 
D - mentioned in para 2.

so now you're down to C and E. For E, at end of passage 2, the author mentions the major eruptions have an impact in the opposite hemisphire, but it doesn't talk about minor eruptions, and for C, the passage talking multiple times of volcanic eruptions. so you may have to guess - the trick is that passage 2 is about global temps and passage 3 is about regional temps. choice C is about major eruptions not having a big impact in regional temps, but the whole passage is about them having, so it'd kind of opposite of what the author is saying.

Anyone have any idea how to eliminate E properly here?

Question 8 - purpose of last para

the author presents the last para really to talk about the effect a volcanic eruption can have. which goes again para 2. he talks about the feedback loop, which is a small change making an impact. C directly talks about this. B, D and E are completely out since the author never mentions them. you may be confused between A and C, because the author mentions a year without summer, but that is the opposite. A feedback loop results in year without summer. Hence C

I totally deserve a kudos for doing this during office time on a Friday

Sajjad1994 · Answer

Explanation

7. The information in the passage provides the LEAST support for which one of the following claims?

Explanation

This is an Except question and looking for the odd man out. Four of the choices are supported by the text; one is not.

(A)  directly echoes  lines 32-37 . The effect of major eruptions on global temperature is discernible—if minor.

(B)  When you compare the conclusion in  lines 32-37  with what  “researchers have generally thought”  as described back in  lines 5-12 , you have to acknowledge that volcanoes aren’t given the same amount of credit for the temperature change that they used to be.

(C)  directly contradicts  (A)  which—as we’ve just seen—itself directly echoes the passage in  Paragraph 3.  So  (C)  is what we want here. The big, big eruptions do have an effect, albeit less than was previously supposed.

(D), (E)  Since  “minor eruptions have no discernible effect on temperature” (lines 30-31) , the hemisphere is irrelevant, so  (D)  and  (E)  follow from Mass and Portman’s findings.

Answer: C

Sajjad1994 · Answer

Explanation

6. The author of the passage would be most likely to agree with which one of the following hypotheses?

Explanation

Despite the tentative nature of the question stem this is an Inference question; we need to find that which is supported, i.e. that which must be true, based on the text. On to the choices:

(A)  contradicts  lines 32-37.  The temperature drop caused by a major eruption is  “only half a degree centigrade or less.”

(B)  The causes of El Niño are never discussed. Certainly the El Niño phenomenon is not attributed to the effect of volcanoes at any point.

(C)  essentially sums up the point of  Para 4  and is correct. The  “year without a summer”  would not be the direct result of a major eruption. Instead, the volcano’s effect (mainly its small drop in temperature) would be  “amplified by climatic feedback loops” (line 41)  in order to  “be blown up into” (lines 55-56)  an exceptionally cold summer season.

(D)  contradicts  Para 3 , which announces Mass and Portman’s finding that  “minor eruptions have no discernible effect on temperature” (lines 30-31) , whereas major ones do cause a temperature drop, albeit a small one.

(E)  Well, of course we’re not explicitly told that El Niño affects  “average hemispheric temperature.”  But its climatic effects are dramatic enough that they have to be subtracted from the data in order to determine what effect volcanoes truly have on climate. So the spirit of (E), which negates the importance of the El Niño phenomenon, is really at odds with the author’s ideas. In any case,  (E)  certainly isn’t inferable from the passage.

Answer: C

VerbalBot · Answer

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Long after the lava has cooled, the effects of a major volcanic

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Long after the lava has cooled, the effects of a major volcanic

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