Weakening Arguments

27 soru

To curb economic losses from bark beetle infestations, timber managers introduced a predatory beetle species that preys exclusively on adult bark beetles during their early spring mating period. Researchers concluded that this biological control measure will significantly increase timber yields over the coming decade. They reason that suppressing adult bark beetle numbers during early spring will prevent the beetles from boring into mature trees and depositing larvae, which cause extensive structural damage to wood tissue. Which of the following, if true, most seriously weakens the researchers' argument?

The vast majority of timber destruction attributed to bark beetles is caused by larvae that hatch from eggs deposited by adult beetles in late autumn, prior to the spring mating period.

Laboratory experiments demonstrate that the introduced predatory beetles consume adult bark beetles at a significantly higher rate when spring ambient temperatures rise.

Chemical pesticides previously used against bark beetles caused temporary foliage discoloration in several non-target tree species.

Logging companies in neighboring timber regions have recently adopted mechanized harvesting equipment that reduces processing times.

In regions where predatory beetle populations increased naturally, timber yields rose during years that also experienced unusually mild winter temperatures.

Cevabı ve açıklamayı göster

Cevap: The vast majority of timber destruction attributed to bark beetles is caused by larvae that hatch from eggs deposited by adult beetles in late autumn, prior to the spring mating period.

Cevap

The argument is most seriously weakened by the finding that the vast majority of timber destruction is caused by larvae hatching from eggs deposited in late autumn, prior to the spring mating period.

The correct answer weakens the argument by demonstrating a critical timing mismatch in the causal chain. The researchers claim that suppressing adult bark beetles during the spring mating period will prevent destructive larvae from damaging timber. However, if the larvae responsible for the vast majority of wood destruction hatch from eggs deposited during the preceding autumn, suppressing spring adults will do nothing to stop the damage caused by larvae already present in the trees.

Adım Adım Çözüm

Identify the conclusion and underlying causal chain

The researchers conclude that introducing predatory beetles in early spring will increase timber yields because suppressing spring adult beetles will prevent them from laying destructive larvae.

Evaluating a weakening question requires isolating the precise link between the premise (spring predation of adults) and the conclusion (reduced wood damage and increased yield).

Identify the critical vulnerability in the reasoning

The argument assumes that spring is the period during which the damaging larvae are produced.

If larvae causing the destruction are produced at a different time, controlling adults in spring will fail to prevent timber damage.

Evaluate option impacts against the vulnerability

The statement specifying that destructive larvae hatch from eggs laid in late autumn breaks the connection between spring adult predation and damage prevention.

Because the eggs leading to larval damage were already deposited months earlier, spring intervention comes too late to protect the timber.

Anahtar Kavram

Weakening Causal Arguments by Breaking Premise-Conclusion Assumptions

Soru 2Soru →

To reduce operational costs and improve network reliability, a telecommunications provider plans to replace all existing copper wire infrastructure in rural districts with fiber-optic cables over the next two years. Corporate executives argue that this upgrade will significantly boost net operating profits from rural service within three years, noting that fiber-optic infrastructure requires 70 percent less routine maintenance than copper and supports higher bandwidth subscriptions. Consequently, the executives conclude that the initial capital expenditure will be quickly offset by reduced maintenance expenses and increased subscription revenues.

Which of the following statements, if true, most seriously weakens the corporate executives' argument?

Subscribers in urban districts who upgraded from copper to fiber-optic cables reported a 90 percent reduction in service interruptions over a three-year period.

The telecommunications provider faces stiffer competition from satellite internet providers in suburban markets than it does in rural districts.

In sparse rural districts, the primary cause of line outages is severe weather that damages above-ground utility poles, making physical repairs to fiber-optic cables five times more expensive per mile than repairs to copper lines.

Many rural subscribers currently use mobile cellular data plans as their primary connection to the internet rather than landline broadband service.

The initial installation cost of fiber-optic cable per subscriber in densely populated urban areas has declined dramatically over the past decade.

Cevabı ve açıklamayı göster

Cevap: In sparse rural districts, the primary cause of line outages is severe weather that damages above-ground utility poles, making physical repairs to fiber-optic cables five times more expensive per mile than repairs to copper lines.

Cevap

The argument is most seriously weakened by the statement that in sparse rural districts, the primary cause of line outages is severe weather that damages utility poles, making physical repairs to fiber-optic cables five times more expensive per mile than repairs to copper lines.

The correct answer demonstrates that while routine maintenance might be lower for fiber-optic cables, emergency repair costs following weather-related damage in sparse rural districts are five times higher than for copper. Because severe weather is identified as the primary cause of outages, these substantially higher repair expenses could easily outweigh routine maintenance savings, directly undermining the executives' conclusion that initial capital expenditure will be quickly offset by maintenance savings.

Adım Adım Çözüm

Identify the conclusion and supporting premises of the argument.

The executives conclude that upgrading rural copper infrastructure to fiber-optic cables will boost net operating profits within three years by offsetting capital expenditures through lower maintenance costs and higher subscription revenues.

Deconstructing the core argument reveals the central claim and its underlying financial assumptions.

Identify implicit assumptions and potential vulnerabilities in the reasoning.

The argument assumes that a 70 percent reduction in routine maintenance translates to a net reduction in total maintenance expenditures, ignoring potential non-routine repair costs specific to rural environments.

Weakening questions require finding evidence that disrupts the link between premises (routine savings) and conclusion (overall profit increase).

Evaluate options for a statement that directly undermines the expected net savings or revenue projections.

The option showing that severe weather repairs for fiber-optic lines in rural areas cost five times as much as copper repairs demonstrates that total maintenance costs may actually increase, directly undermining the financial rationale.

Substantial unexpected repair expenses erode the projected net profit margin, exposing a critical flaw in the executives' cost-offset projection.

Anahtar Kavram

Weakening Arguments via Alternative Financial Liabilities and Overlooked Costs

Soru 3Soru →

A logistics company recently provided ergonomic mechanical keyboards to all data-entry clerks at its main fulfillment facility, while clerks at its secondary facility continued using standard keyboards. Over the following six months, reported cases of repetitive wrist strain at the main facility dropped by 40 percent compared to the previous year, whereas reported cases at the secondary facility remained unchanged. Management concluded that replacing standard keyboards with ergonomic mechanical keyboards was responsible for the reduction in wrist strain injuries. Which of the following, if true, most seriously weakens the management's argument?

Prior laboratory studies on ergonomics indicated that typing on mechanical switches significantly reduces muscle fatigue in the hands.

At the start of the six-month period, the main facility introduced automated voice-recognition software that reduced the average daily hours clerks spent typing by half.

Clerks at the secondary facility expressed higher dissatisfaction with their working conditions than did clerks at the main facility.

Ergonomic mechanical keyboards are substantially more expensive to purchase and maintain than standard keyboards.

The company plans to upgrade the computer monitors at both facilities within the next fiscal year.

Cevabı ve açıklamayı göster

Cevap: At the start of the six-month period, the main facility introduced automated voice-recognition software that reduced the average daily hours clerks spent typing by half.

Cevap

The argument is most seriously weakened by the statement that the main facility introduced automated voice-recognition software that halved the daily typing time required of clerks.

The correct answer introduces a major confounding variable: at the same time the keyboards were deployed, automated software cut the daily typing load of clerks by half. Because reduced typing duration directly lowers repetitive strain risk, this alternative cause accounts for the drop in injury claims without requiring the keyboards to be responsible.

Adım Adım Çözüm

Identify the conclusion and main evidence of the argument.

Premise: Wrist strain claims fell 40% at the main facility after new keyboards were introduced, but stayed constant at the secondary facility. Conclusion: The new keyboards caused the drop in wrist strain claims.

Understanding the premise-to-conclusion structure isolates the causal claim being made.

Determine the flaw or vulnerability in the causal reasoning.

The argument assumes that no other factor changed at the main facility during the six-month trial that could explain the drop in strain claims.

To weaken a causal claim based on a comparison, look for an unaddressed alternative cause that co-occurred with the intervention.

Evaluate the choices to find an alternative cause for the outcome.

The statement introducing voice-recognition software provides a compelling alternative cause (fewer hours of typing), which explains the 40% decrease independently of the keyboard design.

An alternative explanation breaks the direct causal link between the keyboards and the injury reduction.

Anahtar Kavram

Weakening Causal Arguments via Alternative Causes

Soru 4Soru →

A recent study conducted in regional agricultural districts showed that farms adopting drip irrigation systems reduced water usage by 30 percent per hectare compared to farms using conventional flood irrigation. To promote water conservation, local authorities plan to subsidize half of the installation costs of drip irrigation systems for all commercial farms in the region, concluding that this program will significantly reduce overall agricultural water consumption. Which of the following statements, if true, most seriously weakens the water authorities' argument?

By significantly lowering per-hectare operational costs, the implementation of drip irrigation will encourage most commercial farmers to convert previously uncultivated land into actively irrigated acreage.

Drip irrigation systems deliver water directly to crop roots, minimizing evaporation loss compared to conventional surface flooding methods.

Municipal and residential water consumption in the region has steadily increased over the past decade due to rapid suburban expansion.

Technological modifications to conventional flood irrigation hardware are expected to make traditional methods moderately more energy efficient within ten years.

Commercial farms in adjacent agricultural districts that did not receive government subsidies historically exhibited low voluntary adoption rates for new equipment.

Cevabı ve açıklamayı göster

Cevap: By significantly lowering per-hectare operational costs, the implementation of drip irrigation will encourage most commercial farmers to convert previously uncultivated land into actively irrigated acreage.

Cevap

The argument is most seriously weakened by the finding that lower per-hectare operational costs will prompt farmers to expand their irrigated acreage, offsetting per-hectare water savings.

The argument relies on the assumption that saving water on a per-hectare basis will automatically reduce total regional agricultural water usage. The correct choice demonstrates that adopting drip irrigation reduces per-hectare costs enough to induce farmers to irrigate more land. This increase in total irrigated acreage can completely offset or exceed the per-hectare water savings, frustrating the authorities' goal of reducing total consumption.

Adım Adım Çözüm

Identify the premises and conclusion of the argument.

Premise: Drip irrigation uses 30% less water per hectare than flood irrigation. Plan: Subsidize drip irrigation installation. Conclusion: Total agricultural water consumption in the region will decrease significantly.

Understanding the logic linking the plan to the intended outcome isolates the core assumption.

Analyze the implicit assumption.

The argument assumes that total cultivated acreage and crop water requirements will remain roughly constant after adopting the new technology.

If efficiency gains lead to an expansion of scale or changes in usage habits, total usage may not decline.

Evaluate the choices to find a statement that undermines the conclusion.

The statement regarding farmers expanding their irrigated land directly undermines the conclusion by showing that total water usage could stay the same or increase despite per-hectare efficiency.

A plan-goal argument is vulnerable if the plan incentivizes behavior that counteracts the desired goal.

Anahtar Kavram

Unintended Consequences and Scale Expansion (Rebound Effect in Plan-Goal Reasoning)

Tahmini Süre:1m 30s

Soru 5Soru →

In 2021, the city of Eldervale implemented a comprehensive urban greening program, planting over 10,000 native trees across its central commercial district. Over the subsequent three years, reported air pollution levels in the district fell by 25 percent, and foot traffic to local businesses increased significantly. City officials concluded that the tree-planting initiative successfully improved the central district's environmental quality, thereby attracting more visitors and driving local economic vitality. Which of the following statements, if true, most seriously undermines the city officials' conclusion?

Concurrent with the greening initiative, the city completed a major highway bypass that rerouted over 60 percent of heavy commercial vehicle traffic away from the central district.

Surveys conducted during the three-year period revealed that visitors specifically cited the shaded aesthetic of the new trees as a primary reason for spending time downtown.

The annual maintenance and irrigation costs for the newly planted native trees exceeded initial municipal budget projections by nearly fifteen percent.

Similar tree-planting initiatives in neighboring cities with significantly different industrial profiles failed to yield measurable reductions in urban air pollution.

The city council had originally planned to pair the tree-planting program with an expansion of pedestrian-only zones, but that expansion was postponed indefinitely.

Cevabı ve açıklamayı göster

Cevap: Concurrent with the greening initiative, the city completed a major highway bypass that rerouted over 60 percent of heavy commercial vehicle traffic away from the central district.

Cevap

The statement noting that the city completed a major highway bypass rerouting heavy vehicle traffic away from the district most seriously weakens the argument.

The author concludes that planting trees caused the drop in air pollution and the increase in visitors. To weaken a causal argument, presenting an alternative factor that independently accounts for the observed effects is an effective strategy. If heavy vehicle traffic—a primary source of urban air pollution and pedestrian disruption—was rerouted away from the district at the exact same time, this bypass provides a compelling alternative explanation for both the 25 percent reduction in pollution and the increase in foot traffic.

Adım Adım Çözüm

Identify the argument's premises and conclusion.

Premises: 10,000 trees were planted; subsequently, air pollution decreased by 25% and foot traffic increased. Conclusion: The tree-planting program caused the environmental improvement, which in turn attracted visitors.

Understanding the precise causal chain (Tree Planting → Better Air Quality & More Visitors) is essential before searching for a weakener.

Identify the logical vulnerability of the argument.

The argument assumes a correlation between two events implies a direct causal relationship, ignoring potential confounding variables or alternative explanations.

Causal claims based on observational changes over time are vulnerable to third-party factors that occurred during the same timeframe.

Evaluate the options to find an alternative cause or counter-evidence.

The opening of a major highway bypass rerouting 60% of heavy commercial traffic accounts for both the drop in air pollution and the improved pedestrian environment/foot traffic independent of the trees.

Demonstrating that another major factor directly caused the observed effects severs the assumed causal link between the tree planting and the outcome.

Anahtar Kavram

Alternative Explanations in Causal Arguments

Tahmini Süre:2m 0s

Soru 6Soru →

Historians long believed that the sudden economic decline of the coastal city of Thalassa in the fourth century BCE was caused by a major earthquake that destroyed its main harbor. However, recent geological surveys confirm that the harbor suffered no structural damage from seismic activity during that era. Researchers therefore conclude that a severe, prolonged drought must have been the primary cause of Thalassa's economic collapse.

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

Pollen samples from sediment layers around Thalassa dating to the fourth century BCE indicate a dramatic drop in agricultural crop yields consistent with arid conditions.

Excavations of domestic dwellings in Thalassa revealed that fourth-century BCE residents increasingly stored water in ceramic jars rather than subterranean cisterns.

Historical records reveal that a newly constructed overland trade highway bypassed Thalassa during the fourth century BCE, causing the majority of regional merchant traffic to reroute.

Seismic events in neighboring inland cities during the fourth century BCE frequently caused severe disruptions to local agricultural production.

Artifacts recovered from Thalassa's market square show a decline in the variety of imported luxury goods beginning in the fifth century BCE.

Cevabı ve açıklamayı göster

Cevap: Historical records reveal that a newly constructed overland trade highway bypassed Thalassa during the fourth century BCE, causing the majority of regional merchant traffic to reroute.

Cevap

The argument is most seriously weakened by the statement that a newly constructed overland trade highway bypassed Thalassa during the fourth century BCE, rerouting merchant traffic.

The argument relies on ruling out seismic harbor damage to conclude that drought was the primary cause of Thalassa's economic downfall. The correct answer introduces a plausible alternative cause—a major shift in regional merchant traffic due to a new overland trade highway—which explains the economic collapse independently of drought. This severely undermines the necessity of the drought conclusion.

Adım Adım Çözüm

Identify the premise and conclusion of the argument.

Premise: Harbor facilities suffered no seismic damage. Conclusion: A prolonged drought must have been the primary cause of Thalassa's economic collapse.

Understanding the logical jump from ruling out harbor earthquake damage to assuming drought causality isolates the argument's core vulnerability.

Identify the logical flaw.

The author assumes a false dichotomy—that if earthquake damage to the harbor did not cause the decline, drought must be the sole remaining primary cause.

To weaken an argument based on an exclusive cause assumption, one should introduce an alternative explanation for the observed outcome.

Evaluate the options for a viable alternative cause.

The rerouting of regional merchant traffic via a new overland highway explains the economic decline without relying on drought.

Providing an alternative cause directly undermines the claim that drought was necessarily the primary driver.

Anahtar Kavram

Weakening an argument by presenting an alternative cause for the observed outcome

Tahmini Süre:1m 30s

Soru 7Soru →

To reduce losses caused by the invasive root-knot nematode, agricultural authorities in Southland introduced a genetically modified soybean strain that produces a nematode-repelling compound in its root exudates. Field trials in pilot regions showed a 40 percent decrease in root damage and a corresponding 25 percent increase in crop yields compared to conventional fields. Consequently, the authorities plan to mandate nationwide commercial planting of this modified strain to boost national agricultural exports.

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

Conventional soybean farmers in neighboring regions have successfully controlled root-knot nematode populations using multi-year crop rotation techniques rather than genetic modification.

Major international buyers that purchase over 80 percent of Southland's soybean exports prohibit agricultural imports from nations where genetically modified crops are commercially cultivated.

In the pilot field trials, the genetically modified soybean strain required significantly lower applications of synthetic chemical pesticides than conventional soybean varieties.

Root-knot nematodes also inflict substantial yield reductions on Southland's domestic corn and wheat crops.

Consumer preference for non-genetically modified foods within Southland's domestic retail markets has increased noticeably over the past decade.

Cevabı ve açıklamayı göster

Cevap: Major international buyers that purchase over 80 percent of Southland's soybean exports prohibit agricultural imports from nations where genetically modified crops are commercially cultivated.

Cevap

The argument is most seriously weakened by the statement that major international buyers purchasing over 80 percent of Southland's soybean exports prohibit imports from nations commercially cultivating genetically modified crops.

The correct answer demonstrates that mandating nationwide planting of the genetically modified soybean will cause Southland's primary foreign buyers—who account for over 80 percent of soybean exports—to ban soybean imports from Southland. Even if domestic production yields increase, the inability to sell to major foreign markets directly defeats the conclusion that national exports will be boosted.

Adım Adım Çözüm

Identify the premise and conclusion of the argument.

Premise: Pilot trials of a GM soybean strain reduced nematode root damage by 40% and increased crop yields by 25%. Conclusion: Mandating nationwide commercial planting of this GM strain will boost national agricultural exports.

Deconstructing the argument isolates the logical leap between higher physical yield in trials and the economic goal of increased exports.

Identify the implicit assumption and potential vulnerability.

The argument assumes that higher soybean yields will translate directly into higher export sales in international markets without regulatory or trade barriers.

Weakening questions require finding evidence that breaks the link between the premise (yield increase) and the conclusion (export boost).

Evaluate the choices to find the statement that undermines the conclusion.

The statement revealing that major international export buyers reject imports from countries commercially cultivating GM crops demonstrates that adopting the strain will block access to primary export markets, neutralizing any yield gains.

This directly defeats the stated objective of boosting national exports.

Anahtar Kavram

Identifying trade barriers or regulatory constraints that decouple physical crop yield increases from national economic export success.

Soru 8Soru →

A city recently installed high-intensity LED streetlights in its commercial district to reduce night-time traffic accidents. Over the six months following the installation, the number of recorded night-time traffic accidents in the district dropped by 25 percent. City officials concluded that the improved visibility from the new LED streetlights was directly responsible for the reduction in traffic accidents. Which of the following statements, if true, most seriously weakens the city officials' conclusion?

Surveys conducted after the installation indicated that drivers found the commercial district's roads much easier to navigate at night.

Three months ago, the city deployed a significantly higher number of traffic police patrols in the commercial district during night-time hours.

High-intensity LED streetlights installed in residential neighborhoods of nearby cities led to an increase in public complaints about light pollution.

The commercial district experienced a higher volume of daytime traffic than night-time traffic both before and after the streetlights were installed.

The new LED streetlights consume significantly less electricity to operate than the traditional lighting fixtures they replaced.

Cevabı ve açıklamayı göster

Cevap: Three months ago, the city deployed a significantly higher number of traffic police patrols in the commercial district during night-time hours.

Cevap

The statement regarding the deployment of significantly higher numbers of traffic police patrols during night-time hours most seriously weakens the argument by providing an alternative cause for the reduction in traffic accidents.

The argument concludes that the new LED streetlights directly caused a 25 percent reduction in night-time accidents. To weaken a causal conclusion, introducing an alternative cause for the same effect is effective. The statement introducing increased traffic police patrols during night-time hours provides an alternative explanation for why accidents declined, casting doubt on whether the streetlights were responsible.

Adım Adım Çözüm

Identify the conclusion and premise of the argument.

Premise: Night-time traffic accidents dropped by 25% after installing LED streetlights. Conclusion: Improved visibility from the LED streetlights directly caused the reduction in accidents.

Understanding the causal claim is essential before evaluating potential weakeners.

Determine what kind of statement would weaken a causal conclusion.

An alternative explanation for the drop in accidents (e.g., another simultaneous intervention) will weaken the claim that streetlights were the direct cause.

Causal arguments are vulnerable when another plausible cause co-occurs with the observed effect.

Evaluate the choices to find an alternative cause or flaw.

The statement about increased police patrols introduces a concurrent change that could independently account for reduced accident rates.

Increased enforcement deters risky driving behaviors, offering a competing explanation for the outcome.

Anahtar Kavram

Weakening Causal Arguments via Alternative Causes

Soru 9Soru →

Agricultural scientists recently developed a genetically modified variety of wheat engineered to produce a natural enzyme that repels the destructive Hessian fly. In controlled laboratory trials, crops of this modified wheat suffered 90 percent less damage from Hessian flies than conventional wheat crops did. The researchers concluded that replacing conventional wheat with this modified variety across Region X will virtually eliminate wheat crop losses caused by the Hessian fly.

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

In the open fields of Region X, soil temperatures during the Hessian fly's peak feeding season inhibit the modified wheat from expressing the repelling enzyme.

Farmers in Region X who participated in preliminary trial surveys expressed high interest in adopting pest-resistant crop strains to reduce chemical pesticide costs.

Hessian flies in Region X also feed on barley crops, which are frequently grown in crop rotation with wheat.

Synthesizing the repelling enzyme in isolation requires complex laboratory procedures involving expensive chemical catalysts.

Historically, wheat crop yields in Region X have fluctuated far more due to annual rainfall variation than due to insect infestation levels.

Cevabı ve açıklamayı göster

Cevap: In the open fields of Region X, soil temperatures during the Hessian fly's peak feeding season inhibit the modified wheat from expressing the repelling enzyme.

Cevap

The argument is most seriously weakened by the statement that soil temperatures in Region X's open fields inhibit the modified wheat from expressing the repelling enzyme during peak fly feeding season.

The conclusion relies on generalizing findings from controlled laboratory trials to open fields in Region X. The correct choice demonstrates that real-world environmental conditions (soil temperatures during peak feeding season) prevent the modified wheat from expressing the protective enzyme. This directly undermines the claim that the new variety will eliminate Hessian fly damage in Region X.

Adım Adım Çözüm

Identify the argument's premise and conclusion.

Premise: Laboratory trials showed modified wheat suffered 90% less Hessian fly damage due to an enzyme it produces. Conclusion: Replacing conventional wheat with modified wheat in Region X will virtually eliminate Hessian fly wheat losses.

Understanding the precise gap between laboratory results and real-world implementation is crucial to identifying a weak point.

Evaluate the underlying assumption.

The argument assumes that conditions in Region X's open fields will allow the modified wheat to produce the enzyme just as effectively as in controlled laboratory conditions.

A valid weakening statement will undermine this crucial connection between lab trials and real-world conditions.

Identify the option that breaks this assumption.

The finding that natural soil temperatures in Region X prevent the wheat from expressing the enzyme during peak feeding season demonstrates that the lab success will not occur in the field.

This directly invalidates the conclusion without introducing out-of-scope factors.

Anahtar Kavram

Evaluating Weakening Arguments (Lab vs. Real-World Application Gap)

Soru 10Soru →

An organic apple orchard installed owl nesting boxes throughout its acreage six months ago to control the local field mouse population without using chemical pesticides. Recent surveys show that the field mouse population in the orchard has declined by 40 percent over the past six months. The orchard owner concludes that the presence of owls attracted by the nesting boxes caused the reduction in the field mouse population. Which of the following, if true, most seriously weakens the orchard owner's argument?

Three months ago, the orchard introduced several feral barn cats specifically trained to hunt field mice across the property.

Analysis of owl pellets collected near the nesting boxes revealed bone fragments of field mice native to the orchard.

Chemical pesticides used in non-organic orchards in the region are more effective at eliminating field mice than biological control methods.

The cost of building and maintaining owl nesting boxes is significantly less than the annual expense of purchasing chemical pesticides.

Regional predatory bird populations have grown steadily across the state over the past decade.

Cevabı ve açıklamayı göster

Cevap: Three months ago, the orchard introduced several feral barn cats specifically trained to hunt field mice across the property.

Cevap

The argument is most seriously weakened by the statement that the orchard introduced several feral barn cats three months ago to hunt field mice across the property.

The correct option introduces a plausible alternative cause for the decline in the field mouse population. Showing that barn cats were introduced during the same period undermines the conclusion that the owls were the cause of the decrease.

Adım Adım Çözüm

Identify the author's conclusion and underlying premises.

Premise: Nesting boxes were installed six months ago, and field mouse populations declined by 40% over the same period. Conclusion: Owls attracted by the boxes caused the decline.

Understanding the precise causal claim is essential for determining how to weaken it.

Determine the logical vulnerability in the argument.

The argument assumes a causal relationship solely based on a temporal correlation between the installation of nesting boxes and the mouse population decline, failing to rule out alternative causes.

Weakening a causal claim typically involves presenting a plausible alternative cause for the observed outcome.

Evaluate the options to find the one that introduces an alternative cause.

The option introducing feral barn cats brought in three months ago provides a competing explanation for the reduction in field mice.

If barn cats reduced the mouse population, the decline cannot be attributed solely or primarily to the owls.

Anahtar Kavram

Weakening Arguments - Alternative Cause

Soru 11Soru →

A municipal public health board recently introduced a high-dose vitamin D supplementation campaign aimed at reducing winter absenteeism among public transit workers. During the six months following the campaign's launch, sick leave days taken by transit employees declined by 22 percent compared to the same period in the previous year. Consequently, the health board concluded that the vitamin D campaign was directly responsible for the decrease in worker absenteeism. Which of the following statements, if true, most seriously weakens the public health board's argument?

During the same six-month period, the transit authority instituted a strict new attendance policy requiring a physician's verification for any absence, which caused a citywide reduction in reported sick days.

Laboratory evaluations confirmed that over 80 percent of participating transit workers achieved optimal blood vitamin D levels by the conclusion of the six-month campaign.

Private corporations operating in neighboring municipalities noted negligible fluctuations in overall employee productivity over the identical timeframe.

Routine vitamin D supplementation has been shown in clinical trials to improve bone mineral density and long-term cardiovascular functioning in working-age adults.

Surveys indicated that transit workers who consistently consumed the provided supplements also reported elevated subjective energy levels during their work shifts.

Cevabı ve açıklamayı göster

Cevap: During the same six-month period, the transit authority instituted a strict new attendance policy requiring a physician's verification for any absence, which caused a citywide reduction in reported sick days.

Cevap

The argument is most seriously weakened by the statement that the transit authority instituted a strict new attendance policy requiring a physician's verification for any absence, which caused a citywide reduction in reported sick days.

The correct answer undermines the argument by introducing a confounding variable that serves as an alternative explanation. If the transit authority introduced a strict attendance policy requiring physician verification at the same time as the campaign, the drop in reported sick leave can be attributed to administrative deterrence rather than improved health from vitamin D. This undermines the conclusion that the health campaign was the direct cause.

Adım Adım Çözüm

Deconstruct the argument into premise and conclusion.

Premise: Sick leave decreased by 22% following the launch of a vitamin D campaign. Conclusion: The campaign was directly responsible for the reduction in absenteeism.

Isolating the causal claim is necessary to understand how to challenge it.

Identify the underlying logical vulnerability.

The author assumes a causal relationship purely based on temporal sequence (correlation vs. causation) and assumes no external confounding factors influenced employee attendance.

Causal claims in critical reasoning are most effectively weakened by demonstrating an alternative cause for the outcome.

Evaluate the choices for an alternative cause or confounding variable.

The implementation of a strict new attendance policy requiring doctor notes provides an alternative reason why workers took fewer reported sick days.

If administrative policy changes caused the attendance change, the health board cannot validly claim that vitamin D was the direct cause.

Anahtar Kavram

Causal Fallacy and Alternative Explanations in Critical Reasoning

Soru 12Soru →

Epidemiologists studying a coastal region noted a strong positive correlation over the past decade between the consumption of locally farmed shellfish and a decreased incidence of chronic systemic inflammation among residents. Reasoning that high concentrations of specific omega-3 fatty acids present in these shellfish directly suppress inflammatory pathways, local health authorities launched a public campaign encouraging all adults in the region to significantly increase their weekly shellfish intake. Which of the following statements, if true, most seriously weakens the argument for the health authorities' recommendation?

Laboratory assays confirm that specific omega-3 fatty acids isolated from the locally farmed shellfish reduce key inflammatory biomarkers in human tissue samples.

Residents of the coastal region who consume large amounts of shellfish also routinely adhere to a traditional diet rich in antioxidant-dense sea vegetables, which independently suppress systemic inflammation.

Commercial shellfish farming operations in the coastal region contribute significantly to the local economy and generate substantial municipal tax revenues.

Chronic systemic inflammation is a primary contributing factor to long-term cardiovascular decay and degenerative joint disorders in aging populations.

The health authorities' campaign does not specify the precise daily dosage of shellfish required to achieve maximal anti-inflammatory outcomes.

Cevabı ve açıklamayı göster

Cevap: Residents of the coastal region who consume large amounts of shellfish also routinely adhere to a traditional diet rich in antioxidant-dense sea vegetables, which independently suppress systemic inflammation.

Cevap

The argument is most seriously weakened by the statement establishing that high-shellfish consumers also regularly eat sea vegetables known to independently inhibit systemic inflammation.

The argument leaps from a correlated observation (shellfish consumption and lower inflammation) to a direct causal conclusion (shellfish intake reduces inflammation). The correct answer weakens this causal claim by introducing a confounding variable: high shellfish consumers also eat sea vegetables that independently inhibit inflammation. This provides an alternative explanation for the observed health benefit, demonstrating that shellfish may not be the cause of the reduced inflammation.

Adım Adım Çözüm

Deconstruct the argument into premises and conclusion.

Premise: Correlation exists between shellfish intake and reduced inflammation. Premise: Shellfish contain omega-3 fatty acids. Conclusion: Increasing shellfish intake will reduce systemic inflammation.

Identifying the causal leap from correlation to causation isolates the vulnerability of the argument.

Identify the logical flaw in the author's reasoning.

The author assumes shellfish consumption is the sole or direct cause of lower inflammation without ruling out third-variable confounding factors.

Causal claims based on observational correlations are highly vulnerable to alternative explanations.

Evaluate options for a statement that provides an alternative explanation for the observed outcome.

The option identifying the simultaneous consumption of anti-inflammatory sea vegetables offers a plausible alternative cause for the lower inflammation levels.

Demonstrating that another dietary factor present in the exact same population independently produces the effect severely undermines the claim that shellfish is responsible.

Anahtar Kavram

Alternative Causal Explanations in Observational Correlations

Soru 13Soru →

To reduce the frequency and severity of wildland fires in the Sierra Nevada, forestry officials initiated a program of extensive underbrush clearing and controlled burning across public forest tracts. Researchers noted that during a subsequent five-year period of severe drought, tracts subjected to underbrush clearing experienced a 40 percent reduction in total burned acreage compared to unmanaged tracts. Consequently, officials concluded that expanding underbrush clearing to all remaining public timberlands in the region will effectively minimize large-scale forest fire damage during future drought cycles. Which of the following statements, if true, most seriously weakens the forestry officials' argument?

In high-altitude timberlands, which comprise the vast majority of remaining public tracts, removing underbrush opens the canopy to sunlight, drying the forest floor and encouraging the rapid growth of invasive, highly flammable grasses during drought conditions.

Private timberlands adjacent to the managed public tracts that did not undergo underbrush clearing experienced fire damage levels identical to those of unmanaged public tracts.

During the five-year drought period, overall rainfall across the Sierra Nevada was significantly lower than the historical average for the region.

The operational expenditure required to conduct underbrush clearing and controlled burns has increased steadily over the past decade due to rising equipment costs.

Forestry officials in neighboring states have recently adopted similar fuel-reduction programs to protect commercial pine plantations.

Cevabı ve açıklamayı göster

Cevap: In high-altitude timberlands, which comprise the vast majority of remaining public tracts, removing underbrush opens the canopy to sunlight, drying the forest floor and encouraging the rapid growth of invasive, highly flammable grasses during drought conditions.

Cevap

The argument is most seriously weakened by the statement that in high-altitude timberlands, which make up the vast majority of remaining public tracts, clearing underbrush opens the canopy to sunlight, drying the forest floor and promoting the growth of highly flammable invasive grasses during drought conditions.

The correct option identifies a key distinction between the initial test tracts and the vast majority of remaining public timberlands. It demonstrates that in these high-altitude remaining tracts, removing underbrush leads to canopy exposure, extreme soil drying, and the rapid proliferation of highly flammable invasive grasses during droughts. Rather than minimizing fire damage, the intervention would exacerbate fire risk in those areas, thereby directly refuting the conclusion that expanding the program will minimize fire damage overall.

Adım Adım Çözüm

Deconstruct the argument structure into premises and conclusion.

Premise: Managed test tracts had 40% less burned acreage during a drought than unmanaged tracts. Conclusion: Expanding underbrush clearing to all remaining public timberlands will effectively minimize fire damage in future droughts.

Identifying the premise-to-conclusion link isolates the core assumption: that the remaining timberlands will respond to underbrush clearing in the exact same beneficial manner as the initial test tracts.

Identify the logical vulnerability in the argument.

The argument assumes that remaining timberlands share the same ecological traits as the initial managed tracts and that the clearing process carries no hidden negative effects that exacerbate fire risks in those unsampled areas.

Weakening questions for plan-goal or generalization structures frequently turn on showing that unstudied target areas differ in ways that make the plan backfire.

Evaluate the options for a statement that undermines the conclusion.

The statement regarding high-altitude timberlands reveals that the remaining tracts differ structurally and that clearing underbrush produces a counterproductive result (drier soil and flammable invasive grasses), directly undermining the plan's effectiveness.

Showing that an action creates conditions that actively increase fire hazard in the target population refutes the claim that the plan will minimize fire damage.

Anahtar Kavram

Weakening Arguments via Unintended Counterproductive Consequences

Soru 14Soru →

Archaeologists analyzing the ancient agricultural settlement of Oakhaven found that soil moisture levels dropped sharply during the eighth century CE, a period corresponding to a recorded increase in regional temperatures. Because crop yields collapsed simultaneously, the archaeologists concluded that the rise in regional temperatures was the direct cause of the soil moisture depletion and the subsequent agricultural collapse.

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

Early in the eighth century CE, residents of Oakhaven diverted the primary river feeding their irrigation network to construct a massive defensive moat, severely curtailing water delivery to surrounding cropland.

Soil samples from uncultivated wild areas surrounding Oakhaven exhibited a moisture decline identical to that measured in the settlement's agricultural fields during the same century.

Historical weather logs from adjacent regions show that periods of higher temperatures in previous centuries frequently coincided with lower overall annual precipitation.

Innovations in grain storage technology developed in the ninth century CE allowed subsequent populations in the region to survive prolonged droughts.

The primary wheat crops cultivated at Oakhaven required slightly higher soil moisture levels to achieve maximum yield than the legume crops grown by nearby nomadic tribes.

Cevabı ve açıklamayı göster

Cevap: Early in the eighth century CE, residents of Oakhaven diverted the primary river feeding their irrigation network to construct a massive defensive moat, severely curtailing water delivery to surrounding cropland.

Cevap

The argument is most seriously weakened by the statement establishing that early in the eighth century CE, Oakhaven residents diverted the primary river supplying their irrigation network to construct a defensive moat, severely curtailing water delivery to cropland.

The correct answer undermines the argument by presenting an alternative explanation for the drop in soil moisture. If the inhabitants diverted the main river for a defensive moat and restricted irrigation to crops, this human intervention directly accounts for the agricultural soil depletion, rendering the conclusion about temperature being the direct cause unconvincing.

Adım Adım Çözüm

Identify the conclusion and premises of the argument.

Premises: Soil moisture dropped and crop yields collapsed during a period of increased regional temperatures. Conclusion: The rise in regional temperatures directly caused the soil moisture depletion and agricultural collapse.

Understanding the precise causal link asserted by the author is essential to targeting its vulnerability.

Identify the underlying assumption or vulnerability in the causal reasoning.

The argument assumes that no alternative factor (such as human intervention or structural changes in water management) caused the drop in soil moisture.

Causal conclusions in Critical Reasoning are vulnerable to alternative explanations for the observed effect.

Evaluate the answer choices to find a statement that introduces a plausible alternative cause for the moisture loss.

The statement regarding the diversion of the main river for a defensive moat provides a direct alternative explanation for why soil moisture in the crops decreased, independent of climate change.

Demonstrating that human actions cut off the irrigation water supply undermines the claim that rising temperatures were the primary cause of the moisture drop.

Anahtar Kavram

Weakening Causal Arguments via Alternative Cause

Soru 15Soru →

A municipal transit agency observed that after introducing free Wi-Fi service on city buses six months ago, overall passenger satisfaction ratings increased by 20 percent. The agency concluded that providing free Wi-Fi service was the primary reason for the increase in passenger satisfaction. Which of the following statements, if true, most seriously weakens the transit agency's conclusion?

During the same six-month period, the transit agency replaced its entire fleet of old buses with brand-new, comfortable, air-conditioned vehicles.

Surveyed passengers frequently noted that free Wi-Fi allowed them to work productively during their daily commute.

Installing Wi-Fi equipment on city buses cost the transit agency significantly more money than originally budgeted.

A neighboring city experienced a similar rise in passenger satisfaction after introducing Wi-Fi on its commuter trains.

The transit agency plans to expand free Wi-Fi service to city train stations by the end of next year.

Cevabı ve açıklamayı göster

Cevap: During the same six-month period, the transit agency replaced its entire fleet of old buses with brand-new, comfortable, air-conditioned vehicles.

Cevap

The correct answer is the option stating that during the same six-month period, the transit agency replaced its entire fleet of old buses with brand-new, comfortable, air-conditioned vehicles.

The conclusion asserts a direct causal relationship between the addition of free Wi-Fi and higher passenger satisfaction ratings. The statement indicating that the fleet was completely replaced with brand-new, comfortable, air-conditioned buses during the exact same timeframe introduces a compelling alternative cause for the increased satisfaction, directly undermining the claim that Wi-Fi was responsible.

Adım Adım Çözüm

Identify the premise and conclusion of the argument.

Premise: Passenger satisfaction rose by 20% after free Wi-Fi was added to buses. Conclusion: Free Wi-Fi caused the rise in satisfaction.

Isolating the causal claim is necessary to understand how to undermine it.

Determine the strategy for weakening a causal claim.

Look for an alternative cause occurring during the exact same timeframe that could account for the increase in satisfaction.

If another major positive change occurred at the same time, the satisfaction surge cannot be attributed solely to the Wi-Fi service.

Evaluate the choices to find a valid alternative cause.

Upgrading the entire bus fleet to new, air-conditioned vehicles provides a clear alternative explanation for higher rider satisfaction.

This alternative cause severely weakens the agency's conclusion that Wi-Fi was the primary driver of the positive ratings.

Anahtar Kavram

Weakening Causal Arguments via Alternative Causes

Soru 16Soru →

To prevent paper degradation caused by seasonal humidity fluctuations, a municipal historical archive recently installed state-of-the-art automated climate-control units throughout its document vault. Based on laboratory tests showing that constant relative humidity eliminates micro-tearing in centuries-old parchment, the head archivist concluded that installing these units will significantly reduce the archive's overall expenditures on document restoration over the next five years.

Which of the following, if true, most seriously weakens the head archivist's conclusion?

Documents stored in environments with stable relative humidity require far fewer chemical stabilization treatments by professional conservators.

The highly specialized refrigerant and routine maintenance required by the new climate-control units cost more annually than the historical annual expense of repairing paper micro-tears.

Several neighboring regional archives plan to install identical climate-control technology once manufacturing supply chain delays resolve.

Prior to the installation of the units, humidity fluctuations caused a greater percentage of physical document damage than light exposure or handling.

Recent advancements in high-resolution digital scanning have allowed researchers to examine rare manuscripts remotely without handling physical originals.

Cevabı ve açıklamayı göster

Cevap: The highly specialized refrigerant and routine maintenance required by the new climate-control units cost more annually than the historical annual expense of repairing paper micro-tears.

Cevap

The statement showing that the annual operation and maintenance costs of the new climate-control units exceed the historical cost of repairing micro-tears weakens the conclusion.

The conclusion claims that installing the climate-control units will lower total expenditures on document restoration. However, overall expenditure depends on both savings and costs. The correct choice demonstrates that the new maintenance and operational expenses exceed the historical costs of repairing the micro-tears, proving that net expenditures will increase rather than decrease.

Adım Adım Çözüm

Deconstruct the argument into premise and conclusion

Premise: Automated climate-control units eliminate humidity fluctuations, which cause parchment micro-tearing. Conclusion: Installing these units will reduce overall expenditures on document restoration over the next five years.

Identifying the logical structure isolates the underlying assumption—namely, that the total financial savings from reduced restoration will exceed the costs associated with the new units.

Identify the central vulnerability in the financial claim

The conclusion relies on net cost reduction (overall expenditures), but only considers the savings side of the equation while ignoring operational costs.

A argument asserting net savings is vulnerable to evidence showing that new operational or overhead expenses outweigh the savings.

Evaluate option choices to find the statement that exposes this vulnerability

The option establishing that ongoing maintenance and specialized refrigerant costs exceed past restoration expenses demonstrates that overall expenditures will rise, not fall.

This directly contradicts the head archivist's claim of reduced expenditures.

Anahtar Kavram

Weakening Causal and Financial Feasibility Arguments

Soru 17Soru →

To reduce the incidence of waterborne gastrointestinal infections, health authorities in Region X distributed advanced home water filtration units to households in high-risk rural villages. Over the subsequent two years, regional health clinics recorded a 25 percent increase in diagnosed cases of waterborne infections among residents of these villages. Concluding that the filtration units were ineffective at removing pathogens, health officials suspended the distribution program. Which of the following, if true, most seriously weakens the health officials' conclusion?

As part of the filter distribution program, health authorities launched an active diagnostic campaign that routinely screened village residents, identifying many mild infections that previously went unrecorded.

Laboratory evaluations of returned filtration units indicated that organic debris accumulated quickly inside the filter housing when routine cleaning instructions were ignored.

In neighboring urban districts where the filtration units were not distributed, rates of waterborne gastrointestinal infections remained stable over the same two-year period.

A majority of surveyed villagers reported that the filtered water tasted substantially better than untreated water from local wells.

The overall financial expenditure required to import replacement filter cartridges exceeded the initial projections of the regional health budget.

Cevabı ve açıklamayı göster

Cevap: As part of the filter distribution program, health authorities launched an active diagnostic campaign that routinely screened village residents, identifying many mild infections that previously went unrecorded.

Cevap

The argument is most seriously weakened by the evidence that an active diagnostic campaign increased the detection and recording of previously uncounted mild infections, explaining the higher case count without implying filter failure.

The correct answer weakens the argument by introducing an alternative explanation for the observed 25 percent increase in recorded infections. If health authorities actively screened residents and uncovered mild cases that previously went undetected, the rise in official case counts reflects improved detection rather than an actual increase in illness or a failure of the water filters.

Adım Adım Çözüm

Deconstruct the argument structure

Premise: Advanced water filters were distributed to rural villages. Premise: Diagnosed cases of waterborne infections rose by 25% over two years. Conclusion: The filtration units were ineffective at removing pathogens.

Identifying the gap between the premise (increase in diagnosed cases) and conclusion (failure of filters) is essential for finding the flaw.

Identify the central assumption and vulnerability

The argument assumes that an increase in *diagnosed cases* reflects an actual increase in *infection rate*, and that this increase was caused by filter inefficiency.

A classic weakening strategy for data-based arguments is to introduce a reporting bias or alternative cause for the statistical shift.

Evaluate the choices to find an alternative explanation

The choice describing the active diagnostic campaign demonstrates that cases were simply being detected at higher rates rather than occurring more frequently, directly undermining the conclusion.

Demonstrating that the data change is an artifact of surveillance method breaks the logical link between case count and filter failure.

Anahtar Kavram

Weakening Arguments - Alternate Explanation / Reporting Bias

Soru 18Soru →

To address severe coastal erosion threatening its municipal beachfront, the town of Marrow Bay constructed a series of artificial offshore reefs designed to dissipate incoming wave energy. Over the two years following the installation, shoreline erosion rates along Marrow Bay decreased by 35 percent. Municipal engineers concluded that the artificial reefs were directly responsible for mitigating shoreline loss by successfully dampening wave impact forces. Which of the following, if true, most seriously weakens the municipal engineers' conclusion?

During the two years following reef installation, an unusual regional shift in atmospheric pressure systems directed major ocean swells away from the entire coastline containing Marrow Bay.

A parallel study of adjacent coastal communities without artificial reefs showed that their beachfronts experienced a marked increase in erosion over the same two-year period.

The long-term structural maintenance costs of the artificial reef over the next decade are projected to exceed the municipality's initial budget allocations.

The observed 35 percent reduction in coastal erosion failed to yield a corresponding increase in local beachfront tourism or municipal revenue.

Hydrological computer models executed prior to the reef construction had predicted an exact 35 percent reduction in incoming wave energy upon completion.

Cevabı ve açıklamayı göster

Cevap: During the two years following reef installation, an unusual regional shift in atmospheric pressure systems directed major ocean swells away from the entire coastline containing Marrow Bay.

Cevap

The correct option is the statement showing that during the two years following reef installation, an unusual regional shift in atmospheric pressure systems directed major ocean swells away from the entire coastline containing Marrow Bay.

The correct answer weakens the argument by introducing an alternative explanation for the observed decrease in coastal erosion. If broader atmospheric pressure shifts redirected major ocean swells away from the entire region, the reduction in erosion along Marrow Bay would have occurred even without the artificial offshore reefs. This severely undermines the engineers' claim of direct causality.

Adım Adım Çözüm

Identify the premise and conclusion of the argument.

Premise: Shoreline erosion dropped by 35% after artificial reefs were installed. Conclusion: The artificial reefs caused the reduction in erosion by dampening wave impact forces.

Isolating the causal claim is essential for evaluating statements that undermine the argument.

Analyze the implicit causal vulnerability.

The argument assumes that no external factor coincidently reduced wave impact or shoreline erosion during the two-year timeframe.

Causal claims based on temporal correlation are vulnerable to alternative external explanations.

Evaluate the choices to find a statement that introduces a compelling alternative cause.

The statement regarding the regional shift in atmospheric pressure systems shows that ocean swells diminished across the entire region due to weather patterns, meaning erosion would have decreased regardless of the reef.

Demonstrating an independent external cause directly undermines the conclusion that the reef was responsible for the erosion reduction.

Anahtar Kavram

Causal Inference and Alternative Explanations in Critical Reasoning

Tahmini Süre:2m 0s

Soru 19Soru →

To protect native trout populations from invasive northern pike, regional conservationists installed a high-frequency acoustic barrier across the narrow inlet leading into Lake Solitude. Over the subsequent two years, monitoring surveys recorded a 40 percent decrease in the northern pike population upstream of the barrier. Concluding that the barrier successfully deterred the invasive species from migrating, officials plan to deploy similar acoustic technology across other regional waterways. Which of the following, if true, most seriously weakens the conservationists' argument?

A severe outbreak of a species-specific bacterial infection drastically reduced northern pike populations throughout the entire river basin during the two-year period.

Laboratory evaluations conducted prior to installation demonstrated that northern pike consistently alter their swimming direction when exposed to high-frequency sound waves.

Native trout populations upstream of the barrier did not show a statistically significant increase in size during the two-year monitoring period.

High-frequency acoustic deterrents installed in coastal marine environments have occasionally disrupted the navigation of non-target sea mammals.

The operational and maintenance costs of high-frequency acoustic barriers are substantially higher than those of physical mesh barriers.

Cevabı ve açıklamayı göster

Cevap: A severe outbreak of a species-specific bacterial infection drastically reduced northern pike populations throughout the entire river basin during the two-year period.

Cevap

The argument is most seriously weakened by the statement that a severe outbreak of a species-specific bacterial infection drastically reduced northern pike populations throughout the entire river basin during the two-year period.

The correct answer weakens the argument by introducing an alternate cause for the observed decline in the upstream northern pike population. If a widespread bacterial infection caused pike populations to plummet across the entire river basin, the population drop upstream would have occurred regardless of whether the acoustic barrier was installed, thereby dismantling the causal conclusion that the barrier caused the reduction.

Adım Adım Çözüm

Identify the argument's premises and conclusion.

Premise: An acoustic barrier was installed, and the upstream pike population dropped by 40% over two years. Conclusion: The acoustic barrier caused the reduction by deterring pike migration.

Understanding the structure isolates the underlying causal inference that must be evaluated.

Identify the implicit vulnerability in the causal claim.

The argument assumes that the acoustic barrier was the sole or primary reason for the observed population decline upstream, ignoring potential alternative causes.

Causal conclusions based on temporal correlation are vulnerable to alternative explanations for the observed outcome.

Evaluate the options for a factor that undermines the causal link.

The statement regarding a basin-wide bacterial infection introduces a strong alternative cause for the population drop that operates independently of the barrier's presence.

If pike populations dropped everywhere due to disease, the 40% drop upstream cannot be reliably attributed to the acoustic deterrent.

Anahtar Kavram

Weakening Causal Inferences via Alternative Causes

Tahmini Süre:1m 30s

Soru 20Soru →

Analysis of fossilized tooth enamel from *Gigantopithecus*, a giant primate that inhabited Southeast Asia during the Pleistocene epoch, revealed consistently low carbon-13 isotope ratios across late Pleistocene specimens. In mammalian herbivores, low carbon-13 ratios reflect a diet dominated by $C_3$ foliage from dense forest canopies, whereas elevated carbon-13 ratios indicate consumption of $C_4$ grasses typical of open savannahs. Because regional climate records show that open grasslands expanded significantly while dense forests shrank during this period, researchers concluded that *Gigantopithecus* went extinct primarily because its rigid dietary dependence on deep-forest $C_3$ vegetation prevented it from adapting to expanding grassland habitats.

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

Fossilized botanical remains indicate that several widespread species of bamboo—a

C_3

plant that yields low carbon-13 signatures—thrived predominantly in open grassland clearings rather than beneath dense forest canopies.

Other large primate species inhabiting the same geographic region during the late Pleistocene experienced severe population declines as dense forest cover diminished.

Carbon-13 isotope ratios in the fossilized tooth enamel of apex carnivores living in Southeast Asia were largely unaffected by shifts between forest and grassland ecosystems.

Early hominin populations in Southeast Asia expanded their territorial range and hunting activities around the same time that *Gigantopithecus* fossil density began to decrease.

Geological evidence demonstrates that regional grassland expansion accelerated significantly during the middle Pleistocene, several hundred thousand years prior to the extinction of *Gigantopithecus*.

Cevabı ve açıklamayı göster

Cevap: Fossilized botanical remains indicate that several widespread species of bamboo—a $C_3$ plant that yields low carbon-13 signatures—thrived predominantly in open grassland clearings rather than beneath dense forest canopies.

Cevap

The argument is most weakened by the finding that bamboo—a

C_3

plant producing low carbon-13 isotope signatures—grew abundantly in open grassland clearings rather than exclusively in dense forests.

The researchers base their conclusion on the assumption that low carbon-13 ratios (indicating

C_3

plant consumption) strictly imply reliance on shrinking dense forest canopies. The correct option demonstrates that bamboo is a

C_3

plant (generating low carbon-13 signatures) that thrived in open grassland clearings. If *Gigantopithecus* fed on bamboo in open clearings, its low carbon-13 levels do not prove it was confined to deep forests, directly weakening the claim that dietary rigidity prevented it from adapting to expanding open environments.

Adım Adım Çözüm

Identify the premises and conclusion of the argument.

Premise 1: Low carbon-13 ratios in teeth reflect a

C_3

plant diet, while high ratios reflect

C_4

grasses.
Premise 2: *Gigantopithecus* teeth showed low carbon-13 ratios during a period when dense forests shrank and grasslands expanded.
Conclusion: *Gigantopithecus* went extinct because it was restricted to deep-forest

C_3

vegetation and could not adapt to expanding grassland habitats.

Deconstructing the argument reveals the underlying assumption: that consuming

C_3

plants requires living in and relying upon dense forest canopies.

Identify the logical vulnerability or unstated assumption.

The argument assumes that

C_3

plants were available only in shrinking dense forests. If

C_3

plants were abundant in open habitats, low carbon-13 ratios would not prove an inability to forage in open environments.

To weaken a causal argument based on proxy evidence, one must break the link between the evidence (low carbon-13) and the inferred constraint (inability to utilize open habitats).

Evaluate the choices to find the statement that undermines this assumption.

The choice showing that bamboo is a

C_3

plant flourishing in open grassland clearings breaks the link. It shows that *Gigantopithecus* could have inhabited and fed in open environments while still producing low carbon-13 tooth signatures.

This provides an alternative explanation consistent with the isotope data that directly contradicts the conclusion of habitat-based starvation.

Anahtar Kavram

Weakening Arguments via Alternative Interpretations of Evidence

Tahmini Süre:2m 0s

Sayfa 1 / 2Sonraki

Weakening Arguments

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