Critical Reasoning Verbal Practice Questions

Question 1 of 5 Hard

Although fullerenes—spherical molecules made entirely of carbon—were first found in the laboratory, they have since been found in nature, formed in fissures of the rare mineral shungite. Since laboratory synthesis of fullerenes requires distinctive conditions of temperature and pressure, this discovery should give geologists a test case for evaluating hypotheses about the state of the Earth's crust at the time these naturally occurring fullerenes were formed. Which of the following, if true, most seriously undermines the argument?

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Correct Answer: D

The argument concludes that the conditions in Earth's crust where naturally occurring fullerenes were found must have been similar to the laboratory conditions under which synthetic fullerenes are created. This conclusion depends on the assumption that natural fullerenes and synthetic fullerenes are fundamentally the same. Option (D) undermines this argument by revealing that naturally occurring fullerenes are arranged in a previously unknown crystalline structure, meaning they are structurally different from laboratory-synthesized fullerenes. Since the two types of fullerenes are not the same, information about the conditions needed to create one type cannot be applied to the conditions that formed the other type.

Question 2 of 5 Medium

Economist: On average, the emergency treatment for an elderly person for injuries resulting from a fall costs $11,000. A new therapeutic program can significantly reduce an elderly person's chances of falling. Though obviously desirable for many reasons, this treatment program will cost $12,500 and thus cannot be justified. Which of the following, if true, most seriously undermines the conclusion of the argument?

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Correct Answer: C

The argument concludes that the new therapeutic program is not justified because its cost ($12,500 per person) exceeds the average cost of emergency treatment for injuries from falls ($11,000 per person). This conclusion relies on the assumption that the $11,000 figure represents the total cost of treating fall-related injuries. To weaken this argument, we need evidence suggesting that the actual cost of treating such injuries may be higher than $11,000. Option C states that long-term pain medication—a frequent result of fall-related injuries—is not included in the $11,000 average cost of emergency treatment. If this additional cost is substantial, the true cost of treating injuries from falls could exceed $12,500, making the therapeutic program potentially cost-effective. By revealing an unaccounted-for expense, Option C undermines the economist's cost comparison and thus weakens the argument.

Question 3 of 5 Hard

The prairie vole, a small North American grassland rodent, breeds year-round, and a group of voles living together consists primarily of an extended family, often including two or more litters. Voles commonly live in large groups from late autumn through winter; from spring through early autumn, however, most voles live in far smaller groups. The seasonal variation in group size can probably be explained by a seasonal variation in mortality among young voles. Which of the following, if true, provides the strongest support for the explanation offered?

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Correct Answer: E

The conclusion states that "the seasonal variation in group size can probably be explained by a seasonal variation in mortality among young voles." In other words, prairie vole groups are smaller from spring through early autumn because young voles experience higher mortality rates during these seasons. To strengthen this argument, we need evidence that provides a reason for increased young vole mortality specifically during spring through early autumn. Option E strengthens the argument by providing a causal mechanism: snakes, a major predator of young prairie voles, are active only from spring through early autumn. This directly explains why young voles would die at higher rates during these seasons, supporting the conclusion that seasonal variation in mortality among young voles explains the seasonal variation in group size.

Question 4 of 5 Hard

A popular beach has long had a dolphin feeding program in which fish are given to dolphins several times a day; many dolphins get as much as half of their food each day there. Although dolphins that first benefit from the program as adults are healthy and long-lived, their offspring have a lower life expectancy than offspring of dolphins that feed exclusively in the wild. Which of the following, if true, most helps to explain the lower life expectancy of offspring of dolphins feeding at the beach compared to other young dolphins?

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Question 5 of 5 Medium

Tiger sharks are common in the waters surrounding Tenare Island. Usually tiger sharks feed on smaller sharks, but sometimes they have attacked tourists swimming and surfing at Tenare's beaches. This has hurt Tenare's tourism industry, which is second only to its fishing industry in annual revenues. In order to help the economy, therefore, the mayor of the island has proposed an ongoing program to kill any tiger sharks within a mile of the beaches. Which of the following, if true, most strongly calls into question the likelihood that implementation of the mayor's proposal will have the desired consequence?

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