LSAT Practice Test 85 - Logical Reasoning 2 – Questions + Answers

Researchers put two electrodes in a pool that a dolphin swam in. When the dolphin swam near the electrodes, the researchers would sometimes create a weak electric field by activating the electrodes. The dolphin would swim away if the electrodes were activated; otherwise it acted normally. The researchers then placed a plastic shield over small organs called vibrissal crypts located on the dolphin’s snout. With the crypts covered, the dolphin no longer swam away when the electrodes were activated.

The statements above, if true, most strongly support which one of the following?

In a study of honesty conducted in various retail stores, customers who paid in cash and received change were given an extra dollar with their change. Few people who received an extra dollar returned it. So, among those who received an extra dollar, most behaved dishonestly.

The answer to which one of the following questions would most help in evaluating the argument?

Dario: The government should continue to grant patents for all new drug compounds. Patents promote innovation by rewarding pharmaceutical companies for undertaking the costly research needed to develop new drugs.
Cynthia: Promoting innovation is certainly important. For this reason, patents should be granted only for truly innovative drugs, not for minor variants of previously existing drugs. Since it is much less expensive to tweak an existing drug than to develop a wholly new one, pharmaceutical companies tend to focus primarily on the cheaper alternative.

Dario and Cynthia disagree over whether

There are only two possible reasons that it would be wrong to engage in an activity that causes pollution: because pollution harms ecosystems, which are valuable in themselves; or, ecosystems aside, because pollution harms human populations. Either way, it would not be wrong to perform mining operations on Mars. Although doing so would pollute Mars, the small human presence needed to run the mining operation would be completely protected from the Martian environment and would suffer no harm.

The conclusion drawn above follows logically if which one of the following is assumed?

A person with low self-esteem will be treated disrespectfully more often than will a person with high self-esteem. Moreover, a recent experiment found that, when people with low self-esteem and those with high self-esteem are both confronted with the same treatment by others, people with low self-esteem are much more likely to feel that they have been treated disrespectfully. Thus, ________.

Which one of the following most logically completes the argument?

Watanabe: To protect the native kokanee salmon in the lake, we must allow fishing of native trout. Each mature trout eats about 250 mature kokanee annually.
Lopez: The real problem is mysis shrimp, which were originally introduced into the lake as food for mature kokanee; but mysis eat plankton—young kokanees’ food. The young kokanee are starving to death. So eradicating the shrimp is preferable to allowing trout fishing.

Which one of the following principles, if valid, most strongly supports Lopez’s conclusion?

If rational-choice theory is correct, then people act only in ways that they expect will benefit themselves. But this means that rational-choice theory cannot be correct, because plenty of examples exist of people acting in ways that result in no personal benefit whatsoever.

The argument above is most vulnerable to criticism on the grounds that it

Winds, the movement of gases in the atmosphere of a planet, are ultimately due to differences in atmospheric temperature. Winds on Earth are the result of heat from the Sun, but the Sun is much too far away from Jupiter to have any significant impact on the temperature of Jupiter’s atmosphere. Nevertheless, on Jupiter winds reach speeds many times those of winds found on Earth.

Which one of the following, if true, most helps to explain the facts cited above about Jupiter and its winds?

Until recently it was widely believed that only a limited number of species could reproduce through parthenogenesis, reproduction by a female alone. But lately, as interest in the topic has increased, parthenogenesis has been found in a variety of unexpected cases, including sharks and Komodo dragons. So the number of species that can reproduce through parthenogenesis must be increasing.

The reasoning in the argument is most vulnerable to criticism on the grounds that the argument

Physician: Clinical psychologists who are not also doctors with medical degrees should not be allowed to prescribe psychiatric medications. Training in clinical psychology includes at most a few hundred hours of education in neuroscience, physiology, and pharmacology. In contrast, doctors with medical degrees must receive years of training in these fields before they are allowed to prescribe psychiatric medications.

Which one of the following principles, if valid, would most help to justify the reasoning in the physician’s argument?

Lobbyist: Those who claim that automobile exhaust emissions are a risk to public health are mistaken. During the last century, as automobile exhaust emissions increased, every relevant indicator of public health improved dramatically rather than deteriorated.

The flaw in the lobbyist’s reasoning can most effectively be demonstrated by noting that, by parallel reasoning, we could conclude that

A recently discovered fossil, which is believed by some to come from Archaeoraptor liaoningensis, a species of dinosaur, can serve as evidence that birds evolved from dinosaurs only if the entire fossil is from a single animal. However, the fossil is a composite of bones collected from various parts of the discovery site, so it does not provide evidence that birds evolved from dinosaurs.

The conclusion drawn in the argument follows logically if which one of the following is assumed?

A new screening test has been developed for syndrome Q. Research has shown that the test yields a positive for syndrome Q whenever the person tested has that syndrome. So, since Justine shows positive on the test, she must have syndrome Q.

Which one of the following most accurately describes a flaw in the reasoning in the argument?

Music historian: In the past, radio stations would not play rock songs that were more than three minutes in length. Rock musicians claimed that such commercial barriers limited their creativity, and some critics argue that only since those barriers have been lifted has rock music become artistic. In fact, however, when these barriers were lifted, the standards for song structures broke down and the music became aimless, because the styles from which rock derived were not well suited to songs of extended length.

Which one of the following is most strongly supported by the music historian’s claims?

Some food historians conclude that recipes compiled by an ancient Roman named Apicius are a reliable indicator of how wealthy Romans prepared and spiced their food. Since few other recipes from ancient Rome have survived, this conclusion is far too hasty. After all, the recipes of Apicius may have been highly atypical, just like the recipes of many notable modem chefs.

The argument does which one of the following?

Wood that is waterlogged or desiccated can be preserved for a significant period, but, under normal conditions, wood usually disintegrates within a century or two. For this reason, archaeologists have been unable to find many remains of early' wheeled vehicles to examine. However, archaeologists have found small ceramic models of wheeled vehicles made at approximately the same time as those early vehicles. Since these models have been much less susceptible to disintegration than the vehicles themselves, the main evidence regarding early wheeled vehicles has come from these models.

Which one of the following is most strongly supported by the information above?

Traditional hatcheries raise fish in featureless environments and subject them to dull routines, whereas new, experimental hatcheries raise fish in visually stimulating environments with varied routines. When released into the wild, fish from the experimental hatcheries are bolder than those from traditional hatcheries in exploring new environments and trying new types of food. Fish raised in the experimental hatcheries, therefore, are more likely to survive after their release.

Which one of the following is an assumption required by the argument?

An analysis of the language in social media messages posted via the Internet determined that, on average, the use of words associated with positive moods is common in the morning, decreases gradually to a low point midaftemoon, and then increases sharply throughout the evening. This shows that a person’s mood typically starts out happy in the morning, declines during the day, and improves in the evening.

The reasoning in the argument is most vulnerable to criticism on the grounds that the argument overlooks the possibility that

Economist: The wages of many of the lowest-paid corporate employees in this country would be protected from cuts by enacting a maximum wage law that prohibits executives at any corporation from earning more than, say, 50 times what the corporation's lowest-paid employees in this country earn. Currently, some executives try to increase corporate profits-and their own salaries-by cutting the pay and benefits of their corporations' employees. A maximum wage law would remove this incentive for these executives to cut the wages of their lowest-paid employees.

Which one of the following is an assumption the economist's argument requires?

The level of triglycerides in the blood rises when triglycerides are inadequately metabolized. Research shows that patients with blood triglyceride levels above 1 milligram per milliliter are twice as prone to heart attacks as others. Thus, itis likely that consuming large amounts of fat, processed sugar, or alcohol, each known to increase triglyceride levels in the blood, is a factor causing heart disease.

Which one of the following, if true, most weakens the argument?

In an experiment, some volunteers were assigned to take aerobics classes and others to take weight-training classes. After three months, each performed an arduous mathematical calculation. Just after that challenge, the measurable stress symptoms of the volunteers in the aerobics classes were less than those of the volunteers in the weight-training classes. This provides good evidence that aerobic exercise helps the body handle psychological stress.

Which one of the following is an assumption the argument requires?

Insurers and doctors are well aware that the incidence of lower-back injuries among office workers who spend long hours sitting is higher than that among people who regularly do physical work of a type known to place heavy stresses on the lower back. This shows that office equipment and furniture are not properly designed to promote workers’ health.

Which one of the following, if true, most undermines the reasoning above?

Researchers have found that some unprotected areas outside of a national park that was designed to protect birds have substantially higher numbers of certain bird species than comparable areas inside the park.

Which one of the following, if true, most helps to explain the researchers’ finding?

A recent poll of a large number of households found that 47 percent of those with a cat had at least one person with a university degree, while 38 percent of households with a dog had at least one person with a university degree. Clearly, people who hold university degrees are more likely to live in a household with a cat than one with a dog.

The reasoning in the argument is flawed in that the argument

Keeler wanted the institute to receive bad publicity. He and Greene were the only ones in a position to tell the press about the institute’s potentially embarrassing affiliations, but Greene had no reason to do so. Therefore, it must have been Keeler who notified the press.

Which one of the following arguments is most closely parallel in its reasoning to the argument above?