All practice questions

Forestry Researcher: Alpine birch trees infested with leaf-mining moths suffer significantly less winter frost injury than uninfested birch stands nearby. Because the larvae generate minute amounts of metabolic heat while burrowing inside leaf tissues during late autumn, this thermal output must directly shield the birch trees from extreme freezing temperatures during the subsequent winter months.

Which of the following, if true, most seriously undermines the forestry researcher's conclusion?

Every manuscript in the municipal archive that was created before 1750 is stored in a climate-controlled vault. Any archive document stored in a climate-controlled vault requires written authorization from the head archivist to be accessed. Today, researcher Evelyn was granted access to a municipal archive document without written authorization from the head archivist.

Based on the statements above, which of the following statements must be true? (Select all that apply.)

Match each argument with the fundamental unstated assumption on which its conclusion logically depends.

Every deep-sea research probe deployed into the Hadal zone that operates below 7,000 meters requires a titanium-composite pressure hull. No probe equipped with a titanium-composite pressure hull can utilize standard acoustic telemetry for real-time surface communication. Any probe that cannot utilize standard acoustic telemetry must record its observational telemetry locally onto solid-state optical drives unless it is tethered directly to a fiber-optic surface buoy. Last season, the Mariana Oceanic Survey deployed six autonomous, untethered probes into the Hadal zone, all of which operated at a depth of 8,200 meters throughout their missions. Furthermore, some probes deployed by the survey last season suffered complete failure of their external imaging sensors.

If all the statements above are true, which of the following statements must also be true? (Select all correct statements.)

Transportation Director: Six months after our municipal transit authority installed high-definition surveillance cameras across central bus terminals, reported pickpocketing incidents decreased by 35 percent. Because the cameras were mounted in prominent, well-marked locations, it is clear that potential thieves were deterred by the visible likelihood of being recorded.

Statement: If it is true that transit authorities also doubled the deployment of uniformed foot-patrol officers across the central terminals throughout the same six months, this fact weakens the Transportation Director's argument.

Match each flawed argument excerpt on the left with the description on the right that most accurately identifies its primary reasoning vulnerability.

Every coral reef ecosystem that is recovering from bleaching must exhibit a high density of herbivorous fish. But a reef can exhibit a high density of herbivorous fish only if it has low nutrient pollution. Consequently, since the Solstice Reef does not have low nutrient pollution, it cannot be recovering from bleaching.

Which of the following arguments is most similar in its logical structure to the argument presented above?

At the Crestview Municipal Library, every employee who manages the archival collection has completed advanced cataloging training. In addition, no employee who has completed advanced cataloging training is permitted to perform public front-desk duties during morning shifts.

If the statements above are true, which of the following must also be true?

Agricultural Advisor: A regional coffee farming cooperative recently reported that member farms using a newly introduced organic compost experienced a twenty percent decrease in crop-damaging beetle infestations compared to the previous year. Because no other new pest control products were distributed to these farms during that period, the cooperative's directors concluded that the compost itself produces compounds that actively repel these beetles.

Which of the following, if true, most seriously weakens the directors' argument?

Botanist: In order for this rare species of orchid to bloom, it must be kept in an environment with high humidity. The greenhouse housing this specimen has maintained high humidity throughout the entire year. Therefore, this orchid will bloom.

Which one of the following most accurately describes the reasoning flaw in the botanist's argument?

A university library recently replaced all of its older fluorescent ceiling lights with energy-efficient LED fixtures that emit a cooler, bluer spectrum of light. During the semester following the installation, the average number of hours students spent studying in the library each evening increased by thirty percent. The university administration concluded that the cooler light spectrum provided by the LED fixtures directly caused students to study for longer periods. Which one of the following is an assumption on which the university administration's argument depends?

Agronomist: In field trials across several arid test sites, cereal crops treated with a newly developed mycorrhizal fungal bio-fertilizer yielded 30 percent more grain per acre than crops treated with standard chemical fertilizers. Because the formulation enhances root nutrient uptake and soil moisture retention without depleting organic matter, switching exclusively to this bio-fertilizer will significantly increase overall grain production across the nation’s drought-prone farming regions.

Which of the following, if true, most seriously weakens the agronomist’s argument?

Ecologist: A plant species can successfully colonize high-salinity coastal marshes only if it produces specialized root membrane transport proteins that actively exclude sodium ions. Recent genetic analysis revealed that the coastal cordgrass population in the northern estuary possesses active genes encoding these specialized transport proteins. Therefore, this cordgrass population will establish a thriving, permanent colony in the northern estuary marshes.

Which one of the following most accurately describes a flaw in the ecologist's reasoning?

Passage A
Evolutionary biologists have long posited that juvenile play in animals serves a strictly utilitarian function: it is a rehearsal for adult survival behaviors. Under this "practice theory," kittens pouncing on balls of yarn are honing their hunting techniques, and wolf pups wrestling are developing the combat skills necessary for establishing dominance and defending territory. Natural selection dictates that animals would not expend valuable calories and expose themselves to predators through play unless it conferred a distinct evolutionary advantage. Thus, the seemingly frivolous antics of young animals are actually serious, genetically programmed drills. From this perspective, every leap, chase, and mock bite can be mapped to a specific adult task required for finding food, evading capture, or mating. The survival-practice model elegantly explains why play behavior is ubiquitous across mammalian species: it provides a safe, controlled environment for acquiring the physical dexterity and neurological coordination essential for navigating a hostile world.

Passage B
The deeply entrenched notion that all animal play is merely a dry run for adult survival skills is increasingly at odds with observational data. While it is tempting to view a wolf pup's wrestling as combat training, this strictly utilitarian framework ignores the sheer exuberance and unstructured nature of much animal play. Observers frequently document animals engaging in spontaneous, creative behaviors—such as otters repeatedly sliding down mudbanks or ravens dropping and catching twigs in mid-air—that have no clear parallel in necessary adult survival tasks. Furthermore, play often involves deliberate self-handicapping and extreme energy expenditure that can temporarily increase vulnerability to predators. A more plausible explanation for these behaviors is that play is intrinsically rewarding. Current neurological research suggests that play stimulates the release of dopamine and reduces cortisol levels, serving primarily as a mechanism for stress relief and social bonding. Rather than being a rigorous evolutionary training program, play may often be an end in itself—a hedonistic pursuit that benefits the animal emotionally rather than strictly preparing it for the rigors of hunting or fighting.

Based on the passages, how would the author of Passage A most likely interpret the behavior of the otters described in Passage B?

Passage A
The sudden appearance of diverse, complex animal body plans in the fossil record, commonly known as the Cambrian explosion, represents one of the most significant events in evolutionary history. The prevailing ecological hypothesis suggests that this rapid morphological diversification was catalyzed primarily by the advent of macroscopic predation. Prior to this period, marine ecosystems were dominated by soft-bodied organisms grazing on microbial mats. The evolution of active predators, equipped with specialized feeding appendages and sensory organs, introduced unprecedented selective pressures. In response, prey species rapidly developed protective adaptations such as calcified exoskeletons, spines, and sophisticated defensive behaviors. This intense biological "arms race" between predators and prey fueled a self-propagating cycle of morphological innovation. The fossilized remains of Anomalocaris, a formidable apex predator, alongside heavily armored trilobites, perfectly encapsulate this dynamic. As predators evolved better ways to capture prey, prey evolved better ways to escape, driving the explosive radiation of anatomically complex taxa. In this view, the engine of the Cambrian explosion was inherently ecological: it was the complex web of new trophic interactions that forced life forms to innovate or perish, thereby sculpting the diverse body plans we recognize today.

Passage B
While the ecological changes characterizing the Cambrian period were undoubtedly profound, attributing the Cambrian explosion solely to a predator-prey "arms race" conflates the survival of new forms with their origin. Ecological pressures can only select from the anatomical variations that are already genetically available. Therefore, the true catalyst for this rapid diversification must be sought at the genomic level. Recent advances in evolutionary developmental biology point to the expansion and duplication of regulatory gene networks, such as Hox genes, as the primary drivers of Cambrian morphological diversity. These genetic regulatory toolkits dictated the body patterning of embryos, establishing the anterior-posterior axis and segment identity. Mutations within these networks could trigger massive, cascading changes in phenotype with relatively minor genetic tweaks. A sudden increase in the complexity of these genetic networks provided organisms with the architectural flexibility to develop novel appendages, specialized segments, and varied body plans. Without this intrinsic developmental plasticity, no amount of external ecological pressure could have conjured such a vast array of complex anatomies. Thus, genetic innovation was the prerequisite foundation; ecological interactions merely served as the sieve through which these newly minted, genetically facilitated variations were subsequently sorted.

Which of the following best describes how the author of Passage B would most likely respond to the assertion in Passage A that the biological arms race "fueled a self-propagating cycle of morphological innovation"?

Premises:
Every musician who performs in the woodwind section of the Metropolis Symphony Orchestra is required to play both the orchestral flute and the piccolo. Julian performs in the woodwind section of the Metropolis Symphony Orchestra.

Statement: Julian is required to play the piccolo.

Passage A
Customary international law, formed by the consistent practice of states out of a sense of legal obligation (opinio juris), is often criticized for its ambiguity. However, this fluidity is its greatest asset. Unlike codified treaties, which freeze legal principles at the moment of signing and often reflect the asymmetric power dynamics of that specific historical juncture, customary law evolves organically. It allows the international legal order to adapt to changing moral landscapes and technological advancements without the cumbersome process of renegotiation. Treaties, by attempting to lock in precise definitions, inevitably become outdated, whereas the iterative nature of state practice ensures that customary law remains persistently relevant. Thus, the foundation of a truly responsive global legal framework must rely primarily on customary norms rather than the brittle rigidity of treaty law.

Passage B
The assertion that customary international law is inherently more adaptable or equitable than treaty law fundamentally misapprehends the nature of democratic legitimacy in the international sphere. True, treaties are static texts, but they are the product of explicit state consent, debated and ratified through established domestic constitutional processes. Customary law, by contrast, is a notoriously opaque mechanism where the actions of a few powerful states can prematurely crystallize into binding norms for the entire international community, often bypassing domestic democratic scrutiny. The "fluidity" of customary law is merely a euphemism for legal uncertainty, which disproportionately disadvantages smaller states that lack the geopolitical influence to shape state practice. Therefore, while treaties require periodic, sometimes arduous, renegotiation, this process of explicit consent is the only mechanism that confers genuine legitimacy on international legal obligations.

Which one of the following most accurately describes a point of disagreement between the authors of the two passages?

A nation's economy achieves sustained hyper-growth if and only if it rapidly modernizes its infrastructure while maintaining a low inflation rate. A nation cannot rapidly modernize its infrastructure unless it attracts significant foreign direct investment. Furthermore, any nation that imposes strict capital controls is unable to attract significant foreign direct investment. Finally, all nations that refrain from imposing strict capital controls experience occasional periods of currency volatility.

If the statements above are true, which one of the following must also be true?

Passage A
For decades, the standard model of evolutionary biology has rested upon the solid foundation of vertical gene transfer—the direct passing of genetic material from parent to offspring. While microbiologists have long recognized that prokaryotes frequently exchange genes horizontally across different species, evolutionary theorists have largely dismissed horizontal gene transfer (HGT) as a meaningful driver of complex eukaryotic evolution. This dismissal is firmly grounded in biological reality. Multicellular eukaryotes possess a strict germline barrier; their reproductive cells are anatomically isolated from somatic cells and effectively shielded from environmental DNA. Consequently, the rare instances of HGT observed in eukaryotic lineages are best viewed as evolutionary anomalies or non-functional genomic clutter, rather than foundational mechanisms of adaptation. To suggest that these isolated events require a paradigm shift in our understanding of eukaryotic development is to mistake a minor biochemical leak for a tidal wave. The traditional "tree of life," characterized by its branching, strictly vertical lineages, remains the most robust and predictive model for understanding the vast majority of eukaryotic diversity.

Passage B
The advent of advanced genomic sequencing has forced a profound reevaluation of the strict vertical-inheritance paradigm that has long dominated evolutionary biology. Evidence is increasingly mounting that horizontal gene transfer (HGT)—the lateral acquisition of genetic material from entirely unrelated organisms—is not restricted to the microbial realm. Instead, it plays a vital, rapidly adaptive role in eukaryotic evolution. Recent genomic studies have demonstrated that various fungi, plants, and even some complex animals, such as bdelloid rotifers and certain nematodes, have incorporated functionally significant foreign genes into their genomes. These acquired genes have frequently facilitated rapid adaptation to extreme environments and the immediate exploitation of new ecological niches, outpacing the slow crawl of vertical mutation. Despite this compelling genomic evidence, some traditionalists cling to the classical "tree of life" model, actively dismissing eukaryotic HGT as mere background noise, anomalous occurrences, or even methodological contamination. This rigid adherence to strict verticality fundamentally misrepresents the messy, web-like reality of evolutionary history. Recognizing HGT as a substantial engine of eukaryotic innovation does not invalidate Darwinian selection, but it undeniably requires abandoning the dogma that complex organisms evolve exclusively through the slow, vertical accumulation of internal mutations.

Based on the passages, which of the following best describes how the author of Passage A would most likely interpret the specific genomic evidence regarding bdelloid rotifers mentioned in Passage B?

Urban Planner: Last spring, the municipal council planted 500 native oak saplings across northern district parks to reduce summer ground temperatures. Recent satellite thermal scans revealed that average surface temperatures in these parks were two degrees Celsius lower this summer than during the previous summer. Therefore, planting the oak saplings was directly responsible for cooling the northern district parks.

Which of the following statements, if true, undermine the urban planner's conclusion? (Select all that apply)