Volcanoes

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TopicsApplicationScience

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Passage

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. Researchers have generally thought that this veil can block enough sunlight to have a chilling 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 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 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 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 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 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 of feedbacks a small temperature drop could be blown up into a year without a summer.

What this question is testing

Application

Your task

Pin down exactly what the question asks about the passage — a detail, the author's view, the structure, or the main point — before looking at the choices.

Common trap

Answers that restate a true detail from the passage but don't answer the specific question being asked.

Winning move

Anticipate the answer in your own words from the passage, then find the choice that matches that prediction.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question

10.

To which one of the following situations would the concept of a feedback loop, as it is employed in the passage,

Answer choices

Correct79% picked this
An increase in the amount of decaying matter in the soil increases the amount of nutrients in the soil, which increases the number of
Why this is right
This gives us a feedback loop. We start with an "increase in the amount of decaying matter in the soil", and so we just want to read to see if the rest of the answer describes some chain reactions that result in "even more increase in the amount of decaying matter in the soil". That does indeed happen. an increase in X leads to Y, which leads to Z, which further increases X
Skill tested: Application · how this choice captures the passage's function is the move to repeat next time.
79%
No Loop8% picked this
An increase in the number of wolves in an area decreases the number of deer, which decreases the grazing of shrubs, which increases the
The initial cause doesn't get amplified, so there is no feedback loop. We start with an "increase in the number of wolves", and so we just want to read to see if the rest of the answer describes some chain reactions that result in "even more increase in the number of wolves". But we never hear about an increase in wolves, just "other animals" in the area.
8%
No Loop2% picked this
An increase in the amount of rain in an area increases the deterioration of the forest floor, which makes it harder for wolves to
The initial cause doesn't get amplified, so there is no feedback loop. We start with an "increase in the amount of rain", and so we just want to read to see if the rest of the answer describes some chain reactions that result in "even more increase in the amount of rain". But we never hear about a further increase in rain.
2%
No Loop9% picked this
An increase in the amount of sunlight on the ocean increases the ocean temperature, which increases the number of phytoplankton in the ocean, which
The initial cause doesn't get amplified, so there is no feedback loop. We start with an "increase in the amount of sunlight", and so we just want to read to see if the rest of the answer describes some chain reactions that result in "even more increase in the amount of sunlight". But we never hear about a further increase in sunlight. In fact we hear the opposite - something starts blocking sunlight.
9%
No Loop3% picked this
As increase in the number of outdoor electric lights in an area increases the number of insects in the area, which increases the number
The initial cause doesn't get amplified, so there is no feedback loop. We start with an "increase in the number of outdoor electric lights", and so we just want to read to see if the rest of the answer describes some chain reactions that result in "even more increase in the number of outdoor electric lights". But we never hear about a further increase in the number of outdoor electric lights.
3%

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