Free SAT Practice Question

Question 1 of 1
ID: DSAT-RW-II-022
Section: Digital SAT Reading & Writing (RW) - Broadly Reading - Information and Ideas
Topic: Command of Evidence – Textual
Difficulty level: Hard

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In southern African savannas, engineers and biologists examined cathedral-like termite mounds to explain how colonies exchange heat and gases. Sensors embedded through the outer shell and central chimney logged temperature, CO₂, and airflow over full day–night cycles. Records showed a consistent pattern: the sun warmed the shell while the inner chimney stayed cooler, creating a vertical gradient that peaked in late afternoon and weakened before dawn. The team hypothesized that these temperature differences—not outside wind—drive convection: buoyant warm air rises through the chimney, drawing cooler outside air inward through porous walls. Because ventilation strength tracked the gradient rather than gusty winds, the researchers predicted that equalizing shell–chimney temperatures would suppress ventilation, whereas amplifying the gradient would enhance it.

Which finding, if true, would most directly support the researchers' hypothesis?

AWhen mounds were wrapped in insulating blankets that equalized shell–chimney temperatures, CO₂ levels rose and tracer-gas exchange dropped sharply, even though external wind speed and colony activity remained constant during the trial.

BIn wind-tunnel tests, sealed model mounds with no internal temperature gradient still showed strong gas exchange whenever external airflow increased, despite sensors confirming equal temperatures in the shell and chimney.

CSurveys found nearby ant nests had similarly porous walls and central chambers, yet their ventilation rates varied widely by species, independent of measured mound microclimates or local wind conditions across the study region.

DWhen researchers heated the shell with infrared lamps to create a larger shell–chimney gradient, chimney updraft did not increase and wall inflow remained unchanged, even under steady wind and stable colony activity.

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