1. The company's strategy involves not only streamlining operational processes and reducing overhead but also to expand into emerging markets and developing new product lines.
Solution
Correct: B
The 'not only X but also Y' construction requires X and Y to be grammatically parallel. In the original sentence, X is 'streamlining operational processes and reducing overhead' (two gerund phrases). Y, however, is 'to expand into emerging markets and developing new product lines' (an infinitive phrase followed by a gerund phrase). This breaks parallelism. Option B correctly uses parallel gerund phrases for both parts of the construction: 'not only streamlining operational processes and reducing overhead but also expanding into emerging markets and developing new product lines.' Option C uses infinitives for both, which would also be parallel, but 'involves streamlining' is already established, making the gerund form more consistent and concise. Option D uses noun phrases ('the expansion,' 'the development'), which breaks parallelism with the initial gerunds. Option E incorrectly alters the 'not only... but also' structure.
2. Despite its revolutionary potential, the inventor's reluctance to patent his new device, fearing it would hinder collaborative development, meant that its widespread adoption was delayed significantly.
Solution
Correct: D
The original sentence has a slight ambiguity regarding the pronoun 'it' in 'fearing it would hinder collaborative development.' 'It' could refer to the patent (the act of patenting) or the device itself. Option D clarifies this by explicitly stating 'fearing that it would hinder collaborative development,' where 'it' unambiguously refers to the act of patenting, which is the logical entity that might hinder collaboration. Furthermore, 'the inventor's reluctance' is the correct subject for 'meant,' as the reluctance, not the inventor, caused the delay. Options B and E incorrectly make 'the inventor' the subject of 'meant,' which is illogical given the introductory phrase 'Despite its revolutionary potential.' Option C changes the meaning slightly by implying the *collaborative development* would be hindered, rather than the *act of patenting* hindering the development.
3. A new diet regimen encourages daily consumption of a specific probiotic supplement. Proponents claim that this regimen significantly boosts the immune system, citing a study where participants on the diet exhibited higher levels of T-cells, crucial components of immune response. However, critics argue that the study is flawed because participants were also advised to exercise regularly, a known immune booster.
Solution
Correct: C
The critics argue that the observed increase in T-cell levels might be due to exercise, not the probiotic supplement. To strengthen the proponents' claim that the probiotic is responsible, one must eliminate or significantly reduce the alternative explanation provided by the critics. Option C does exactly this: if a control group that *only* exercised (without the supplement) showed no significant T-cell increase, it directly refutes the idea that exercise alone caused the T-cell boost, thereby strengthening the conclusion that the probiotic is the causal factor. Option A does not eliminate exercise as a factor; it only states that more rigorous exercise didn't yield *greater* increases. Option B suggests a potential flaw in the study, which would weaken, not strengthen, the claim. Option D is irrelevant to the core argument about exercise versus the specific probiotic. Option E introduces another potential confounding factor (restriction of processed foods), which would suggest something *other* than the probiotic could be responsible, thereby weakening the claim.
4. Unlike many species of migratory birds, the Arctic Tern's annual migration route covers a far greater distance than any other known animal, traversing nearly 50,000 miles.
Solution
Correct: B
The original sentence makes an illogical comparison: it compares 'the Arctic Tern's annual migration route' (a route) to 'any other known animal.' For a comparison to be logical, it must compare similar things. Option B correctly compares 'the Arctic Tern's annual migration route' to 'that of any other known animal,' where 'that' correctly refers to 'the migration route,' ensuring a parallel and logical comparison between two routes. Options A and E repeat the illogical comparison. Option D corrects the comparison by making 'the Arctic Tern' the subject, but the introductory modifier 'Unlike many species of migratory birds' correctly introduces a comparison between species, so keeping the Arctic Tern as the subject would be appropriate for that. However, the original sentence structures the comparison around the *route*, making option B the most direct and grammatically sound correction for maintaining that structure. Option C introduces an unnecessary comma and 'it traverses,' making the sentence awkward and less concise.
5. Historians have long believed that the invention of the printing press was an instrumental factor for the widespread dissemination of knowledge, accelerating the Renaissance and facilitating the Reformation.
Solution
Correct: C
The original sentence uses the phrase 'an instrumental factor for,' which is less idiomatic and more wordy than 'instrumental in.' The adjective 'instrumental' (meaning 'serving as a means; helpful') followed by 'in' is the correct and more concise idiom ('instrumental in [doing something]'). Option C correctly uses the idiom 'was instrumental in' and is more concise than using 'an instrumental factor.' The past tense 'was' is appropriate because the historians' belief (expressed in the present perfect 'have long believed') refers to an event (the invention of the printing press) and its historical consequences (Renaissance, Reformation) that are completed. Option B uses the past perfect 'had been,' which is incorrect as there is no later past event that necessitates this tense. Option E uses the present perfect 'has been,' which implies the invention's instrumental role is still actively unfolding from the perspective of the historians' belief, which is not the case for these historical events. Options A and D retain the awkward and wordy 'an instrumental factor for.'
6. Studies indicate that regular consumption of red wine, in moderation, is correlated with a lower incidence of heart disease among adults. However, red wine also contains alcohol, which is known to be a liver toxin and increases the risk of certain cancers. Therefore, advising the general public to consume red wine for heart health would likely have adverse public health consequences overall.
Solution
Correct: A
The argument presents two sides: red wine for heart health (a benefit) versus its risks as a liver toxin and cancer risk (negative effects). The conclusion states that advising its consumption would have 'adverse public health consequences overall.' This 'overall' assessment directly implies that the negative effects are considered to be more significant or to outweigh the potential benefits. Therefore, the most reasonable inference is that the benefits of moderate red wine consumption for heart health are outweighed by its negative effects on other organs. Option B might be true but is not a direct inference from the *given* argument, which focuses on red wine itself. Option C is not implied; the argument weighs the *impact* of red wine, not the inherent public health importance of various diseases. Option D is an assumption about public behavior, not an inference from the provided facts. Option E is not directly inferable; the argument doesn't deny the correlation or its potential causality but focuses on the *net* public health impact.
7. The collection of rare artifacts, along with several newly discovered manuscripts, are being prepared for exhibition at the museum, where it is hoped they will attract a significant number of visitors.
Solution
Correct: D
The subject of the sentence is 'The collection,' which is singular. Phrases like 'along with several newly discovered manuscripts' are parenthetical and do not change the number of the subject. Therefore, the verb must be singular: 'is being prepared,' not 'are being prepared.' This eliminates options A and C. In the latter part of the sentence, 'where it is hoped they will attract a significant number of visitors,' the pronoun 'they' correctly refers to the multiple items within the collection and the manuscripts (the artifacts and manuscripts collectively), which are the things that will attract visitors. Option B incorrectly uses 'it' to refer to both the collection and manuscripts, which would be awkward as 'it' typically refers to a singular entity. Option E changes the verb tense to 'attracts' and uses 'it' again. Option D correctly uses the singular verb 'is being prepared' for 'The collection' and the plural pronoun 'they' for the artifacts and manuscripts that will attract visitors.
8. Often considered a precursor to modern existentialism, Kierkegaard's philosophical writings explore the individual's profound freedom and the burden of choice, concepts which have profoundly influenced subsequent thinkers.
Solution
Correct: C
The opening modifier 'Often considered a precursor to modern existentialism' must logically modify a person, Kierkegaard, not 'Kierkegaard's philosophical writings.' Options A, B, and D fail to correct this dangling modifier. Options C and E correctly place Kierkegaard as the subject. The clause 'concepts which have profoundly influenced subsequent thinkers' is a restrictive clause, meaning it provides essential information to identify *which* concepts are being discussed, so 'that' is preferred over 'which.' This eliminates the 'which' in options A. Between C and E, option C uses 'explored' (past tense), which is more appropriate as Kierkegaard's writings and their initial exploration of these concepts occurred in the past, leading to a long-term influence. Option E uses the present tense 'explores' and a participial phrase 'profoundly influencing' which is less precise than a full clause for conveying the historical influence of specific concepts. Therefore, option C is the best choice for fixing the modifier, using the correct relative pronoun, and maintaining appropriate tense.
9. A new study claims that children who play violent video games are more likely to exhibit aggressive behavior. The study surveyed 1,000 children, asking them about their gaming habits and observing their behavior in controlled play sessions. However, the study relied on self-reported gaming data, and the observed aggressive behavior was limited to minor incidents like pushing and verbal outbursts.
Solution
Correct: E
The study concludes that violent video games *cause* aggressive behavior. The most significant flaw in such a correlation-causation argument is often the possibility of reverse causation. Option E directly addresses this by asking if children who are *already* aggressive are more likely to play violent video games. If this were true, the observed correlation would be explained by pre-existing aggression leading to gaming choices, rather than the games causing aggression, thus severely undermining the study's conclusion. Option A (age) is a demographic detail but doesn't challenge the causal link as fundamentally. Option B (game type) refines the scope but not the causality. Option C (parental attitudes) introduces another factor, but less directly challenges the video game-aggression link than reverse causation. Option D (definition outside study) is less critical as the study's observations were limited to controlled sessions.
10. The company's decision to decentralize its operations, a strategy implemented to boost local responsiveness, has been met with mixed results, because it has led to inefficiencies in resource allocation.
Solution
Correct: A
The original sentence (Option A) is grammatically sound and idiomatically correct. 'Has been met with mixed results' is a standard and appropriate passive construction, implying that the decision received or encountered these results. The pronoun 'it' clearly refers to 'the company's decision,' which logically 'has led to inefficiencies.' The present perfect tense ('has been met,' 'has led') is appropriate for describing a situation that began in the past (the decision) and whose effects (mixed results, inefficiencies) continue or have current relevance. Other options introduce less precise or less idiomatic phrasing, or grammatical issues: Option B uses 'for boosting' (less idiomatic than 'to boost' for purpose) and 'having led' (a participle phrase that is less direct for causation than 'because it has led'). Option C uses the simple past 'met' and 'led,' which implies the situation is entirely concluded, possibly altering the intended meaning that the results are *still* mixed. Option D changes to active voice 'has met with mixed results,' which is generally acceptable but perhaps less idiomatic for 'results' than 'been met with.' Option E is wordier with 'implemented as a strategy' and uses the less direct 'having led.' Given the choices, the original sentence (A) is the most precise, idiomatic, and grammatically correct.
11. Having undergone extensive repairs, the engineers launched the bridge, which had been damaged by the recent earthquake, back into service ahead of schedule.
Solution
Correct: B
The introductory participial phrase 'Having undergone extensive repairs' must logically modify the subject of the main clause. In the original sentence (A), this phrase modifies 'the engineers,' incorrectly implying that the engineers, not the bridge, underwent repairs. This is a classic dangling modifier error. Option B corrects this by making 'the bridge' the subject of the main clause, so the phrase 'Having undergone extensive repairs' correctly refers to the bridge. It also maintains conciseness and clarity. Option C places the modifier at the end, making it ambiguous about what 'having undergone' refers to. Option D is grammatically awkward and verbose. Option E uses 'After undergoing extensive repairs,' but the subject of the main clause is still 'the engineers,' so the modifier still dangles.
12. A prominent tech analyst predicted that the sales of virtual reality (VR) headsets would skyrocket this year, citing the increasing availability of affordable models and the growing number of VR-compatible games. However, a recent market report shows that VR headset sales have remained stagnant. This demonstrates that consumers are not interested in virtual reality technology, regardless of price or content.
Solution
Correct: D
The argument concludes that stagnant sales indicate consumers are *not interested* in VR technology. This is a strong conclusion from sales data alone. Option D weakens this conclusion by providing an alternative explanation for stagnant sales: consumers *are* interested but are delaying purchases for other reasons (e.g., waiting for next-generation technology, specific future content, or more polished ecosystems). This directly challenges the leap from 'stagnant sales' to 'no interest.' Option A suggests the prediction was wrong but doesn't explain why the *conclusion* about consumer interest is flawed. Option B addresses the definition of affordability but doesn't explain a general lack of interest. Option C suggests the content isn't compelling enough, but doesn't rule out underlying interest. Option E introduces a competing factor, which could explain *some* of the sales stagnation but doesn't directly refute the claim about a lack of interest in VR *itself* as forcefully as Option D.
13. To excel in modern competitive sports requires not only rigorous physical training but also to develop mental fortitude, as much as athletes need to analyze their opponents' strategies.
Solution
Correct: D
The sentence uses the correlative conjunction 'not only X but also Y,' which requires X and Y to be grammatically parallel. The first part, 'rigorous physical training,' is a noun phrase. Therefore, the second part should also be a parallel noun phrase or gerund phrase. The original sentence's 'to develop mental fortitude' (an infinitive phrase) breaks this parallelism. Furthermore, the ending 'as much as athletes need to analyze their opponents' strategies' is awkward and verbose. Option D correctly uses parallel gerund phrases ('developing mental fortitude and analyzing their opponents' strategies') to align with 'rigorous physical training,' making the entire list of requirements parallel and concise. Option A and E retain the infinitive, breaking parallelism. Option B uses 'the development of mental fortitude' (a noun phrase) but retains the awkward 'as much as athletes need to analyze.' Option C uses a gerund but then switches to 'an analysis,' breaking parallelism within the 'as well as' clause.
14. Studies have indicated that the human brain, which is an organ whose complexity is unparalleled in the natural world, requires a disproportionately high amount of the body's total energy intake to function.
Solution
Correct: B
The original sentence contains wordiness and redundancy in the descriptive clause 'which is an organ whose complexity is unparalleled in the natural world.' Option B, 'an organ of unparalleled complexity in the natural world,' is a concise and grammatically correct appositive phrase that efficiently conveys the same meaning without unnecessary words. This makes the sentence more direct and readable, which is preferred in GMAT Sentence Correction. Option C incorrectly changes the main verb 'requires' to a participle 'requiring,' creating a sentence fragment (lacking a main verb for 'brain'). Options A, D, and E are all more verbose or grammatically less precise. Option D is clunky and less direct ('the complexity of which'). Option E adds 'and requires,' changing the structure to make 'brain' the subject of two separate verbs connected by 'and,' but the description remains wordy.
15. A pharmaceutical company is considering launching a new drug for a rare genetic disorder. Clinical trials have shown that the drug effectively slows the progression of the disorder in 70% of patients. However, the company faces high manufacturing costs for the drug. A company executive argues that despite these costs, the drug will be highly profitable because there is no other effective treatment currently available for this disorder.
Solution
Correct: D
The executive's argument is that the drug will be 'highly profitable' despite high manufacturing costs, primarily due to the lack of alternative treatments. While the absence of alternatives allows for a high price, it does not guarantee that patients (or their insurance providers) will be willing *and able* to pay such a high price. For the drug to be highly profitable, the revenue generated must significantly exceed the high manufacturing costs. This revenue depends on both the number of patients and the price they pay. Option D directly addresses this critical link: if patients are not willing or able to pay a high price, then profitability, despite the lack of alternatives, is not guaranteed. Option A (patent protection) is important for *long-term* profitability but not the immediate profitability claim based on lack of alternatives. Option B (ineffective patients) affects overall revenue but not the core pricing strategy. Option C (market size) is a necessary condition for profitability but, like the lack of alternatives, does not by itself guarantee that prices can be set high enough to ensure *high* profitability. Option E (side effects) relates to market adoption, which is essential, but the core issue for profitability given *high costs* is the ability to charge a high enough price.
16. In the rainforest, the diversity of insect species is often significantly greater than that of all other animal groups combined, a phenomenon that perplexes many entomologists.
Solution
Correct: C
The original sentence (Option A) makes a logically sound comparison: 'the diversity of insect species' is compared to 'that of all other animal groups combined,' where 'that' correctly stands for 'diversity.' This is a grammatically correct and common comparative construction. However, Option C offers a slightly more direct and concise way to express the same comparison: 'significantly greater than the combined diversity of all other animal groups.' By directly stating 'the combined diversity,' it avoids the slight redundancy of 'that of' when the full noun phrase is already present and clearly parallel. Both are correct, but GMAT often favors conciseness and directness when meaning is preserved. Option B and D create an illogical comparison between 'diversity' and 'animal groups.' Option E uses 'more significant,' which is less precise than 'significantly greater' when referring to magnitude, and incorrectly uses 'which' for a restrictive clause ('a phenomenon that perplexes'). Therefore, Option C, while very close to A, is marginally more direct and concise.
17. While generally supportive of free trade, the newly elected government has indicated that it intends to protect key domestic industries by raising tariffs and a review of existing trade agreements.
Solution
Correct: B
The phrase 'by raising tariffs and...' requires parallelism for the two actions the government intends to take. 'Raising tariffs' is a gerund phrase. Therefore, the second action must also be a gerund phrase, or a phrase introduced by 'by' to maintain parallelism. The original sentence (A) breaks this parallelism by using a noun phrase, 'a review of existing trade agreements.' Option B correctly maintains parallelism by using 'by raising tariffs and by reviewing existing trade agreements.' The repetition of 'by' emphasizes that both actions are means to the same end and are parallel. Option C is grammatically awkward and verbose ('by the raising of tariffs'). Option D breaks the parallelism and conciseness with 'also reviewing.' Option E changes the structure to 'intend to raise tariffs and a review,' which also lacks parallelism.
18. A new study concludes that people who regularly consume artificial sweeteners are at a higher risk of developing type 2 diabetes. Researchers observed a large population over ten years, noting sweetener consumption and diabetes incidence. They controlled for obesity, age, and family history. This suggests that artificial sweeteners directly contribute to the onset of type 2 diabetes.
Solution
Correct: A
The study concludes a causal link: artificial sweeteners *directly contribute* to type 2 diabetes. To weaken a conclusion of direct causation from a correlation, the best approach is often to provide an alternative cause or demonstrate reverse causation. Option A introduces the possibility of reverse causation: people *already at risk* for diabetes might consume artificial sweeteners as a preventative measure. If this is true, then the correlation observed in the study would be explained by their pre-existing health conditions (which are risk factors for diabetes) causing both the sweetener consumption and the eventual development of diabetes, rather than the sweeteners causing diabetes. This significantly weakens the study's causal conclusion. Option B points to an uncontrolled variable, which weakens the study, but less directly refutes the causal claim than reverse causation. Option C describes a general trend but doesn't explain the specific correlation in the study. Option D refers to external studies, which are not as direct a challenge to the internal logic of *this* study. Option E provides a potential *mechanism* for causation, which would strengthen, not weaken, the conclusion.
19. While the company's initial proposal promised significant cost savings through automation, it has since been revealed to contain several unrealistic assumptions, causing concern among investors.
Solution
Correct: D
The original sentence (Option A) is grammatically acceptable and the pronoun 'it' clearly refers to 'the company's initial proposal.' The participial phrase 'causing concern among investors' correctly modifies the entire preceding clause (the revelation of unrealistic assumptions). However, Option D offers a more precise and impactful phrasing. By replacing 'causing concern' with the appositive 'a revelation that has caused concern among investors,' Option D explicitly states *what* caused the concern – the 'revelation' itself, rather than implying the assumptions directly cause the concern (though the revelation of them certainly does). This phrasing is more precise and emphatic, a characteristic often valued in GMAT for clarity and conciseness where meaning is enhanced. Option B uses an unnecessary past perfect 'had promised.' Option C uses 'as containing,' which is less idiomatic than 'to contain,' and 'which causes' changes the meaning and tense. Option E retains the less precise 'causing concern' and less idiomatic 'as containing.'
20. Despite significant government investment in public transportation infrastructure over the past decade, a recent study indicates that the average commuter's travel time has actually increased by 15%. This suggests that the investments have not achieved their intended goal of reducing congestion and improving commute efficiency.
Solution
Correct: A
The argument presents a paradox: significant investment in public transportation, yet an increase in average commute times. To explain this surprising finding, we need a factor that could counteract the positive effects of public transport improvements. Option A provides a strong explanation: if the growth in private vehicle ownership has dramatically increased during the same period, then overall road congestion could still worsen significantly, leading to longer commute times for everyone, including public transport users (if they use roads for parts of their journey) or those who might have switched from private to public transport but are still caught in wider congestion. This factor overwhelms the benefits of public transport investment. Option B suggests the projects aren't finished, but the problem states 'over the past decade,' implying a period for completion. Option C explains why people might not switch but doesn't explain why existing commute times *increased*. Option D points to a potential flaw in the study's measurement but doesn't explain the underlying reality if the measurement is accurate. Option E indicates a *positive* outcome for public transport, which would deepen the paradox, not explain it.
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