Theodora: You are wrong in claiming that vegetarianism cannot lead to nutritional deficiencies. If most people became vegetarians, some of those losing jobs due to the collapse of many meat-based industries would fall into poverty and hence be unable to afford a nutritionally adequate diet.
Summarize Argument: Counter-Position
Theodora concludes that Marcia is wrong in claiming that vegetarianism cannot lead to nutritional deficiencies. She supports this by saying that if most people became vegetarians, those in meat industries would lose their jobs, fall into poverty, and struggle to afford a healthy diet.
Identify and Describe Flaw
This is an example of a “straw man” argument, where the author misrepresents her opponent’s argument, making it easier to attack. Here, Theodora concludes that Marcia is wrong in claiming that vegetarianism cannot lead to nutritional deficiencies. But Marcia never made this claim. Instead, Marcia claimed that not all vegetarian diets lead to nutritional deficiencies. So Theodora is attacking a distorted version of Marcia’s argument, rather than her actual argument.
A
is directed toward disproving a claim that Marcia did not make
Theodora’s argument is directed toward disproving the claim that vegetarianism cannot lead to nutritional deficiencies. But Marcia merely claimed that not all vegetarian diets lead to nutritional deficiencies.
B
ignores the results of the research cited by Marcia
Theodora does ignore Marcia’s research, but this isn’t what makes her argument most vulnerable to criticism. Even if she had addressed Marcia’s research, her argument would still be vulnerable to criticism on the grounds that it misrepresents a key claim made by Marcia.
C
takes for granted that no meat-based industries will collapse unless most people become vegetarians
Theodora assumes that some meat-based industries would collapse if most people became vegetarians. She doesn't assume that no meat-based industries would collapse unless most people became vegetarians.
D
uses the word “diet” in a nontechnical sense whereas Marcia’s argument uses this term in a medical sense
This is the cookie-cutter flaw of equivocation, where the same term is used in different ways. Theodora doesn’t make this mistake; she uses the word “diet” in the same way as Marcia.
E
takes for granted that people losing jobs in meat-based industries would become vegetarians
Theodora assumes that people in meat based-industries would lose their jobs if most people became vegetarians. She never assumes that the people who lose their jobs would all become vegetarians themselves.
Summarize Argument
The musicologist claims that the piano should be called a percussion instrument as opposed to a stringed instrument. This is because the mechanical process through which an instrument produces sound determines how it should be classified, and the strings which vibrate to produce piano sounds do so because of the impact of hammers.
Identify Conclusion
The conclusion is that the piano should be classified as a percussion instrument as opposed to a stringed one: “the piano is properly called a percussion instrument, not a stringed instrument.”
A
Musical instruments should be classified according to the mechanical actions through which they produce sound.
This is a premise. The musicologist uses this to support the conclusion that the piano is a percussion instrument.
B
Musical instruments should not be classified based on the way musicians interact with them.
This idea is not discussed in the stimulus.
C
Some people classify the piano as a stringed instrument because of the way the piano produces sound.
The musicologist does not make a claim about whether or why some people classify the piano as a stringed instrument.
D
The piano should be classified as a stringed instrument rather than as a percussion instrument.
(D) is trying to trick to us! The musicologist is arguing that the piano should be classified as a percussion instrument rather than a stringed instrument, not the other way around!
E
It is correct to classify the piano as a percussion instrument rather than as a stringed instrument.
This rephrases the conclusion.
Summary
Agricultural runoff from a river has caused phosphorus levels to double in an ocean region.
The phosphorus causes the stimulation of plankton growth near the ocean surface.
The plankton decay and fall to the floor, where bacteria eat them and consume oxygen.
This oxygen depletion means that few fish can survive in the region.
The phosphorus causes the stimulation of plankton growth near the ocean surface.
The plankton decay and fall to the floor, where bacteria eat them and consume oxygen.
This oxygen depletion means that few fish can survive in the region.
Very Strongly Supported Conclusions
The agricultural runoff and the phosphorus contribute to the plankton growth, the oxygen depletion, and the fishes’ inability to survive in the region.
A
The agricultural runoff pouring out of the river contributes to the growth of plankton near the ocean surface.
Very strongly supported. The agricultural runoff contributes to the growth of plankton because it caused phosphorus levels to double, which in turn caused the stimulation of plankton growth.
B
Before phosphorus levels doubled in the ocean region, most fish were able to survive in that region.
Unsupported. Higher phosphorus levels have contributed to fish being unable to survive in the region. But we don’t know whether most fish could survive before phosphorus levels doubled.
C
If agricultural runoff ceased pouring out of the river, there would be no bacteria on the ocean floor devouring decaying plankton.
Unsupported. If the agricultural runoff stopped, there might be fewer plankton and fewer bacteria devouring decaying plankton. But we don’t know that there would be no bacteria devouring decaying plankton.
D
The quantity of agricultural runoff pouring out of the river has doubled in the past few decades.
Unsupported. Agricultural runoff has caused phosphorus levels to double in the past few decades. This doesn’t mean that the runoff itself has doubled in the past few decades.
E
The amount of oxygen in a body of water is in general inversely proportional to the level of phosphorus in that body of water.
Unsupported. It’s true that in this specific region, the water’s oxygen levels have decreased as its phosphorus levels have increased. But this is due to a particular chain of events. We don’t know that oxygen and phosphorus levels are inversely proportional in general.
Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that drivers feel possessive of their parking spots, and increasingly possessive when other drivers want their parking spots.
Notable Assumptions
The author believes that the drivers took more time leaving their spots when other cars were around because they were possessive of their spots. He therefore assumes there’s not some other factor (i.e. the fact there’s a car nearby as they’re leaving the spot) preventing drivers from leaving their spots as quickly as they would when there aren’t other cars around.
A
The more pressure most drivers feel because others are waiting for them to perform maneuvers with their cars, the less quickly they are able to perform them.
Drivers aren’t possessive when other cars are around. They’re simply feeling pressure, which makes them slow down while leaving their spots.
B
The amount of time drivers spend entering a parking space is not noticeably affected by whether other drivers are waiting for them to do so, nor by whether those other drivers are honking impatiently.
We don’t care what happens when drivers enter a spot. We care what happens while they’re leaving a spot.
C
It is considerably more difficult and time-consuming for a driver to maneuver a car out of a parking space if another car waiting to enter that space is nearby.
This explains why drivers took longer to leave the space than when no cars were waiting, but it doesn’t explain why honking intensified the effect. We need to know why that caused drivers to slow down even more.
D
Parking spaces in shopping mall parking lots are unrepresentative of parking spaces in general with respect to the likelihood that other cars will be waiting to enter them.
We don’t care about how frequently this scenario occurs.
E
Almost any driver leaving a parking space will feel angry at another driver who honks impatiently, and this anger will influence the amount of time spent leaving the space.
Even without the honking, drivers still took longer to leave when another car was waiting for the spot. We need to explain why that is.
Shark teeth are among the most common vertebrate fossils; yet fossilized shark skeletons are much less common—indeed, comparatively rare among fossilized vertebrate skeletons.
"Surprising" Phenomenon
Why are fossils of sharks’ teeth so common while fossils of their skeletons are rare?
Objective
The right answer will be a hypothesis that explains a key difference between the teeth and skeletons of ancient sharks. That difference must result in fossilized teeth being more likely to be found, either because there are actually a higher number of fossilized teeth in the world or else because something makes it easier to discover those tooth fossils.
A
Unlike the bony skeletons of other vertebrates, shark skeletons are composed of cartilage, and teeth and bone are much more likely to fossilize than cartilage is.
This explains a key difference between the teeth and skeletons of sharks. Shark skeletons, which are composed of cartilage, are much less likely to fossilize than shark teeth. Because of this, fossilized shark teeth are more likely to be found than fossilized shark skeletons.
B
The rare fossilized skeletons of sharks that are found are often found in areas other than those in which fossils of shark teeth are plentiful.
This doesn’t explain the difference between shark teeth and shark skeletons or account for why fossilized shark skeletons are so rare. Fossilized shark skeletons and teeth may end up in different areas, but we still don’t know why fossilized shark teeth are more plentiful.
C
Fossils of sharks’ teeth are quite difficult to distinguish from fossils of other kinds of teeth.
The stimulus tells us that shark teeth fossils are common. We can’t assume that those fossils are misidentified just because it’s difficult to distinguish them from fossils of other teeth. Also, we still have no information about why fossilized shark skeletons are so rare.
D
Some species of sharks alive today grow and lose many sets of teeth during their lifetimes.
We can’t assume that something that applies to some shark species alive today also applies to those species that are now fossilized. Also, even if ancient sharks did lose lots of teeth, we still have no explanation for why fossilized shark skeletons are so much more rare.
E
The physical and chemical processes involved in the fossilization of sharks’ teeth are as common as those involved in the fossilization of shark skeletons.
If the fossilization processes of shark teeth and skeletons are equally common, it seems that the fossils should be equally common as well. We need a key difference between the two, not a similarity, in order to explain why tooth fossils are more common than skeleton fossils.
Summary
The author concludes that photographs are interpretations of reality. This is based on the fact that photographers express their own worldviews in their photographs.
Missing Connection
Does expressing one’s own worldview constitute an “interpretation of reality”? It might seem like a reasonable assumption, but it’s still an assumption. It’s not explicitly stated, nor is it something that must be true based purely on the definitions of “expressing a worldview” or “interpretation of reality.” So we’re looking for “Expressing one’s worldview constitutes interpreting reality.”
A
Even representing a subject realistically can involve interpreting that subject.
(A) establishes that a realistic representation “can” involve interpreting the subject. But this doesn’t guarantee that it always constitutes an interpretation of reality. (A) leaves open the possibility that some photos are not interpreting reality, even if other photos “can” involve interpreting reality.
B
To express a worldview is to interpret reality.
The premise establishes that photographs express worldviews. In connection with (B), we can conclude that photographs interpret reality.
C
All visual art expresses the artist’s worldview.
We already know that photos express the photographers’ worldviews. What’s missing is whether such expression constitutes interpreting reality. (C) doesn’t tell us that such expression constitutes interpreting reality.
D
Any interpretation of reality involves the expression of a worldview.
(D) reverses what we’re looking for. We want to know that all expressions of worldviews involve interpretations of reality. But (D) asserts that all interpretations of reality involve expressions of a worldview. This leaves open the possibility that some expressions of worldviews might not involve interpretations of reality.
E
Nonrealistic photographs, like realistic photographs, express the worldviews of the photographers who take them.
We already know that photos express the photographers’ worldviews. What’s missing is whether such expression constitutes interpreting reality. (E) doesn’t tell us that such expression constitutes interpreting reality.
Summarize Argument
The author concludes that the marks are traces of geological processes rather than worms. This is because the tracks were made long before multicellular life existed.
Notable Assumptions
The author believes that the only two things that could’ve made the marks are worms and geological processes. Thus, the author assumes there’s no relevant third factor that could’ve been responsible for the marks.
A
It is sometimes difficult to estimate the precise age of a piece of sandstone.
We don’t need the precise age. The marks were made millions of years before the advent of multicellular animal life.
B
Geological processes left a substantial variety of marks in sandstone more than half a billion years before the earliest known multicellular animal life existed.
This strengthens the author’s argument. If geological processes left a variety of marks, then some of those marks could’ve been the ones that look like they were left by worms.
C
There were some early life forms other than worms that are known to have left marks that are hard to distinguish from those found in the piece of sandstone.
These marks were left well before multicellular life existed. This talks about early life forms “other than worms,” which suggests these life forms were contemporaneous with worms.
D
At the place where the sandstone was found, the only geological processes that are likely to mark sandstone in ways that resemble worm tracks could not have occurred at the time the marks were made.
While worms are out of the question, so are geological processes. There must be some other explanation that the author overlooks.
E
Most scientists knowledgeable about early animal life believe that worms are likely to have been among the earliest forms of multicellular animal life on Earth, but evidence of their earliest existence is scarce because they are composed solely of soft tissue.
These marks were made millions of years before multicellular animal life existed. Regardless of how early worms were relative to other forms of animal life, they were still millions of years too late to leave the marks.
Summary
An organ or body structure is often the only mean of accomplishing a task. It is unsurprising that a type of organ or body structure may evolve at different times in unrelated species. Animals share fundamentally similar needs despite differences in heritage and habitat.
Strongly Supported Conclusions
Different animals may develop similar organs to accomplish the needs they share.
A
will often live in the same environment as other species quite different from themselves
This is unsupported because the stimulus provides no information to predict where different animals will live.
B
will in many instances evolve similar adaptations enabling them to satisfy these needs
This is strongly supported because we are told that sometimes an organ or physical structure is the only way of accomplishing a function. So if different animals have the same functions they need to accomplish, they may develop similar organs to accomplish those functions.
C
will develop adaptations allowing them to satisfy these needs
This is unsupported because although needs may be satisfied through adaptations, answer choice B does a better job of noting that the similarity of needs will likely result in a similarity of adaptations.
D
will resemble other species having different biological needs
This is antisupported because if other species have different biological needs, and needs may be met with unique organs designed for specific functions, species with different needs would likely develop organs that do not resemble each other’s.
E
will all develop eyes or wings as adaptations
This is unsupported because we don’t know that the common needs all animals share would be satisfied by eyes or wings.