Strengthen

Agricultural Researcher: In a recent field study, apple orchards that maintained wildflower strips between tree rows had 40 percent fewer infestations of codling moth larvae than adjacent orchards with bare soil between rows. Because wildflower strips attract parasitic wasps that lay eggs in codling moth larvae, the researchers concluded that the presence of these wasps was responsible for the lower infestation rates in the wildflower-bordered orchards.

Which one of the following, if true, most strengthens the agricultural researchers' argument?

Match each short argument on the left with the evidentiary finding on the right that most effectively strengthens its central conclusion.

Match each brief argument with the supplementary finding that most effectively strengthens its reasoning by ruling out a competing alternative explanation.

To reduce errors during the preparation of sterile injectable medications, a regional hospital network required pharmacy technicians to wear high-visibility vests designating 'no-interruption zones' during compounding tasks. Over the twelve months following the policy's introduction, compounding errors fell by 35 percent across all network facilities. Because observational logs confirmed that unscheduled interruptions during compounding also dropped by 70 percent over that same period, administrators concluded that the reduction in interruptions was the primary cause of the decrease in medication errors.

Which of the following, if true, most strengthens the administrators' argument?

Hospital Administrator: Six months ago, our surgical recovery ward replaced standard ceiling panels with specialized acoustic dampening tiles. In the six months following the installation, patients in this ward requested 28 percent fewer doses of supplemental pain medication than patients admitted during the six months immediately preceding the renovation. However, acoustic monitoring revealed that ambient noise levels dropped by only 2 decibels—a change imperceptible to the human ear. Since this minor physical sound reduction could not account for such a marked improvement, the decline in pain medication requests was most likely the result of a placebo effect caused by patients' awareness that the hospital had upgraded the facility.

Which of the following, if true, most strengthens the hospital administrator's argument?

Marine Biologist: Benthic gastropods (*Alviniconcha*) residing near deep-sea hydrothermal vents in sulfide-rich plumes harbor chemosynthetic endosymbionts in their gill tissues and possess notably thicker shells than conspecifics inhabiting iron-dominated plumes, which consistently lack these endosymbionts. Because thicker shells confer greater structural defense against hydrostatic pressure, the biologist concludes that metabolic activity of the endosymbionts directly promotes shell thickening by concentrating dissolved calcium ions.

Statement: The finding that *Alviniconcha* specimens transferred from iron-dominated plumes to sulfide-rich plumes develop thicker shells only when their gill tissues become successfully colonized by chemosynthetic bacteria strengthens the marine biologist's argument.

Ecologist: Over the past decade, populations of the yellow-bellied marmot in a subalpine valley have emerged from hibernation an average of three weeks earlier than they did thirty years ago. Some researchers attribute this shift primarily to rising spring temperatures. However, during the same thirty-year period, local winter snowpack depth decreased by nearly forty percent, exposing burrow entrances to direct sunlight much earlier in the season. Because marmots awaken primarily in response to ambient light penetrating their burrow entrances rather than ambient air temperature, the earlier emergence is almost certainly a result of reduced snowpack rather than warmer air.

Which of the following, if true, most strengthens the ecologist's argument?

Geothermal power facilities in the Salton Rift circulate hot subterranean brine to drive turbines, after which the cooled fluid is reinjected deep underground. An energy consortium recently proposed extracting dissolved lithium from this brine prior to reinjection. Industry critics contend that commercial extraction will accelerate mineral scaling within reinjection wells, precipitating costly pipe blockages and rendering operations economically unviable. However, plant engineers argue that the extraction process will not increase well-clogging rates, noting that the chemical adsorbent used to capture lithium also extracts dissolved silica precursors from the brine. Which of the following, if true, most strengthens the plant engineers' argument?

Urban Planner: Last year, the city of Greenfield introduced a subsidized bicycle-sharing program in its downtown core to reduce rush-hour automobile congestion. Despite high enrollment in the program, traffic sensor data indicated that downtown automobile volume during peak hours did not decrease. Several city council members concluded that the bicycle-sharing program had no effect on reducing car trips. However, their conclusion overlooks the fact that during the same year, a major regional bridge closure diverted thousands of commuter vehicles into Greenfield's downtown streets that would have otherwise bypassed the city.

Which of the following, if true, most strongly supports the urban planner's argument?

Match each argument on the left with the evidentiary finding on the right that most effectively strengthens its central conclusion.

Archaeologist: Excavations at the Bronze Age settlement of Tell el-Marwa revealed that grinding stones from the early occupational layer were made exclusively from local sandstone, whereas those from the late layer were predominantly made from imported basalt. Because basalt is significantly harder and more durable than sandstone, producing finer flour with far less stone grit, researchers concluded that the inhabitants switched to basalt primarily to improve the dietary quality and texture of their grain products.

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

An archival library installed ultraviolet-filtering window film in its main exhibition gallery to safeguard historical manuscripts displayed in open showcases. Curators observed that over the six months following the installation, the rate of ink fading on the exhibited manuscripts slowed considerably compared to prior records. The curators concluded that the installation of the ultraviolet-filtering film was the direct cause of the decreased ink fading. Which one of the following, if true, most strengthens the curators' argument?

Consider the following argument:

Ecologist: In a controlled municipal study, urban green roofs planted exclusively with native sedum species supported a 40 percent higher abundance of native bees than roofs planted with non-native sedum species. Because both groups of roofs had identical total floral surface area and were situated in identical urban microclimates, the higher bee abundance on native sedum roofs must be driven primarily by the superior nutritional quality of native sedum nectar.

Statement: If native bees show no difference in visual attraction to the flower morphology and coloration of native versus non-native sedum species, this finding strengthens the ecologist's conclusion.

The following arguments each rely on unstated assumptions to establish a causal conclusion. Match each argument with the evidentiary finding that most effectively strengthens its central conclusion.

Match each logical argument on the left with the supplementary premise on the right that most effectively strengthens its central conclusion.

Forestry researcher: In high-elevation pine forests, stands treated with mechanical thinning showed a significantly lower rate of bark beetle infestations over a three-year observation period than adjacent untreated stands. Because thinning increases the spacing between trees, thereby increasing sunlight penetration and reducing tree competition for soil moisture, the researcher concluded that reduced water stress directly enhanced the trees' physiological capacity to produce defensive resin against beetles.

Statement: The finding that elevated wind speeds in thinned forest stands physically disperse and dilute the aggregation pheromones used by bark beetles to coordinate mass attacks strengthens the forestry researcher's conclusion.

A wildlife conservation team observed that a local population of river otters experienced a substantial increase in breeding success shortly after commercial fisheries in the river basin switched from traditional nylon nets to a newly designed biodegradable netting. The team concluded that the transition to biodegradable netting was directly responsible for the rebound in the otter population.

Which of the following, if true, most strengthens the conservation team's argument?

Historians studying a nineteenth-century coastal port observed that merchant shipping logs recorded a sharp decrease in shipwrecks near a treacherous submerged reef following the construction of a lighthouse in 1842. Based on this correlation, the historians concluded that the beam from the new lighthouse was directly responsible for the reduction in wrecks by warning navigators away from the hazard.

Which of the following, if true, most strengthens the historians' argument?

Paleoclimatologist: Speleothems (mineral deposits such as stalagmites) in a highland cavern preserve distinct annual layers with oxygen isotope ratios ($\delta^{18}\text{O}$) that fluctuate in response to rainfall. Analysis of a stalagmite spanning the eleventh to thirteenth centuries reveals a pronounced forty-year interval of highly enriched $\delta^{18}\text{O}$ values, indicative of diminished local precipitation. Because historical agricultural annals from the adjacent low-lying river valley record widespread crop failures and village abandonment during this identical forty-year window, researchers conclude that a prolonged regional drought caused the abandonment of these agrarian settlements.

Statement: The finding that drought-sensitive teak trees throughout the adjacent river valley exhibited an unprecedented suppression in annual growth-ring widths during the same forty-year interval logically strengthens the paleoclimatologist's conclusion.

Historian: In fourteenth-century southern Germany, the acute shortage of mature oak timber used for municipal bridge and cathedral construction was historically attributed by chroniclers to the Great Famine and the Black Death, which supposedly decimated the skilled labor force needed to manage and fell old-growth stands. However, recent dendroclimatological analyses of preserved river revetments indicate that between 1310 and 1345, the region experienced unprecedented multi-year periods of severe spring flooding and saturated soils. Oak taproots are uniquely vulnerable to fatal fungal root rot when submerged for extended periods, which halts trunk maturation and induces premature dieback. Therefore, climatically driven tree mortality, rather than a demographic labor collapse, was the primary cause of the structural timber deficit.

Which of the following, if true, most strengthens the historian's argument?