LSAT 148 - Section 3 - Question 07

July 25, 2014

Expert: Some people claim that, since food production has thus far increased faster than population has, there is no need to be concerned about widespread food shortages. These people fail to recognize that the planet’s resources allow for food to be produced at only a few times the current amount, beyond which no increase in production will be possible. Thus, widespread food shortages are inevitable.

Summarize Argument
The expert concludes that widespread food shortages will definitely happen. This is based on the claim that the planet’s resources will only allow for only a certain amount of increase in food production from now, after which no more increases will be possible.

Notable Assumptions
The expert assumes that the world population will eventually grow past the point where the maximum food production allowed by the planet’s resources is enough.

A
The world’s food resources, though limited, are renewable.
This doesn’t help the argument, because it doesn’t establish that the world’s population will ever exceed the level supported by maximum food production. In fact, it tells us nothing at all about population.
B
Food resources from the world’s oceans will eventually be fully utilized.
This is irrelevant, since the expert has already established that there is a maximum amount of food production allowed by the planet’s resources; it doesn’t make a difference to point out where those resources might come from.
C
The world’s population has recently remained fairly stable because of falling birth rates.
This weakens by undermining the expert’s assumption that the world population’s food needs will surpass what the earth can produce. If the population continues to be stable, even the planet’s current food production should still be enough to prevent food shortages.
D
Periodic regional food shortages have occurred at least briefly throughout history.
This is irrelevant, since the expert’s prediction of widespread food shortages in the future doesn’t rely on any evidence of regional food shortages occurring in the past.
E
Population will continue to grow at least briefly when food production has reached its maximum level.
This strengthens by affirming the expert’s assumption that the world population’s food needs will surpass what the earth can produce.

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LSAT 148 - Section 3 - Question 01

July 25, 2014

4 comments

LSAT 148 - Section 3 - Question 02

July 25, 2014

Archaeologist: For 2,000 years the ancient Sumerians depended on irrigation to sustain the agriculture that fed their civilization. But eventually irrigation built up in the soil toxic levels of the salts and other impurities left behind when water evaporates. When its soil became unable to support agriculture, Sumerian civilization collapsed. A similar fate is thus likely to befall modern civilizations that continue to rely heavily on irrigation for agriculture.

Summarize Argument
The author concludes that modern civilizations that continue to rely heavily on irrigation for agriculture are likely to collapse. This is based on a comparison to the ancient Sumerian civilization, which relied on irrigation for agriculture. After irrigation built up toxic levels of salts and other impurities in the soil, the Sumerian civilization collapsed.

Notable Assumptions
The author assumes that the problem of toxic levels of salts and other impurities faced by the Sumerians is likely to face modern civilizations that rely on irrigation for agriculture.

A
Most modern civilizations could not feed themselves through agriculture without relying heavily on irrigation.
This suggests modern civilizations need irrigation to feed themselves through agriculture. But this doesn’t relate to whether such reliance will lead to collapse from toxic soil.
B
Factors unrelated to the use of irrigation would probably have caused Sumerian civilization to collapse sooner or later.
Even if other factors would have led to the Sumerian collapse, that doesn’t change the fact that toxic soils contributed to the Sumerian collapse or whether what happened to the Sumerians will happen to modern civilizations.
C
Many modern farmers use irrigation techniques that avoid the buildup of salts and other toxic impurities in the soil.
This points out why what happened to the Sumerians might not happen to modern civilziations. Modern techniques might not lead to toxic levels of salt and impurities in soil.
D
Many modern civilizations do not rely to any significant extent on irrigation for agriculture.
We’re concerned with what happens to the ones that do rely on irrigation for agriculture. But whether these kinds of civilization are common or rare doesn’t relate to whether these kinds, however many there are, will collapse.
E
The soil of ancient Sumeria already contained some toxic salts and other impurities before the Sumerians started using irrigation for agriculture.
We have no reason to think modern soil doesn’t also contain some toxic salts and other impurities. In addition, even if modern soil doesn’t already have this, that just means it might take longer for the collapse. But (E) doesn’t suggest there wouldn’t be a collapse.

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LSAT 148 - Section 3 - Question 03

July 25, 2014

Researcher: Dinosaur fossils come in various forms, including mineralized bones and tracks in dried mud flats. However, mineralized dinosaur bones and dinosaur tracks in dried mud flats are rarely found together. This isn’t surprising, because creatures that scavenged dinosaur carcasses most likely frequented mud flats to find food.

Summarize Argument: Phenomenon-Hypothesis

The researcher concludes that it isn’t surprising that dinosaur bone fossils are rarely found near fossilized dinosaur tracks in mud flats. This observation is explained with the hypothesis that animals that scavenged dinosaur carcasses often searched for food in mud flats.

Notable Assumptions

The researcher assumes that dinosaur bones could have been moved away from the dinosaur tracks by the activity of creatures that scavenge dinosaur bones in mud flats. The researcher also assumes that there isn’t an alternate explanation for dinosaur bones and tracks often being separated in mud flats.

A
Dinosaur tracks are also found in locations other than mud flats.

This is irrelevant, since the the researcher’s hypothesis only aims at explaining dinosaur tracks that are in mud flats; no conclusions are being drawn about other types of locations.

B
Scavengers commonly drag a carcass away from the site where it was found.

This strengthens the argument by providing a mechanism for the separation of dinosaur bones from tracks by scavenger activity. This affirms the researcher’s assumption that scavenger activity can lead to tracks and bones being separated.

C
Researchers have found more fossil dinosaur tracks than fossil dinosaur bones.

This is irrelevant, since the hypothesis doesn’t depend on the relative frequency of tracks and bones, only the observation that they are rarely found together in mud flats.

D
Dinosaur fossils other than mineralized bone or tracks in dried mud flats are quite common.

This is irrelevant, since the researcher doesn’t make any claims about other types of dinosaur fossils, and only seeks to explain why bones and tracks are rarely found together in mud flats.

E
It takes longer for bone to mineralize than it takes for tracks to dry in mud flats.

This is irrelevant, because how long bones take to mineralize has no bearing on whether or how those bones can be moved away from their original location by scavengers.


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LSAT 148 - Section 3 - Question 04

July 25, 2014

Electric stovetop burners would cause fewer fires if their highest temperature were limited to 350ºC (662ºF), which provides more than enough heat for efficient and effective cooking. The lowest temperature at which cooking oil and most common fibers ignite is 387ºC, and electric burners on high go well above 700ºC.

Summarize Argument: Causal Explanation
The author tells us that limiting the temperature of electric stove burners to 350°C would cause fewer fires. This is supported in two ways: first, by telling us that some flammable items (oil and most fabric) need to be heated above this point to catch fire; and second, by stating that electric burners can currently go far above the temperature needed to ignite these items. By establishing that a fire risk currently exists, and that this limit would reduce or eliminate it, the author supports the conclusion that setting the limit would lead to fewer fires.

Identify Conclusion
The conclusion is the author’s claim about lowering fire risk: “Electric stovetop burners would cause fewer fires if their highest temperature were limited to 350°C (662°F).”

A
Electric stovetop burners would cause fewer fires if their highest temperature were limited to 350ºC.
This is where the author states the conclusion. Everything else in the argument is meant to convince us that this claim is true.
B
A maximum temperature of 350ºC provides more than enough heat for efficient and effective cooking.
This is used to explain that stoves would still be useful with the proposed limitation, but doesn’t actually form part of the argument about lowering fire risk. This is not supported by anything else, nor does it provide support to the conclusion.
C
The lowest ignition temperature for cooking oil and most common fibers is 387ºC.
This is a premise that supports the conclusion, because it shows that keeping stoves below this temperature would mean a lower risk that oil and fabric near the stove could catch fire.
D
Electric burners on high go well above 700ºC.
This is a premise that supports the conclusion, because it shows that stoves currently reach a high enough temperature to ignite some materials that might come near the burners.
E
Electric stovetop burners cause fires because they go well above 700ºC when set on high.
The argument implies that this is true, but this claim acts as support for the conclusion that limiting stovetop temperatures would reduce the number of fires. That makes it a sub-conclusion at best, not the main conclusion.

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