By the time the first cool front drifts into the Rio Grande Valley each October, the groves remember. They remember 1933, when a white crust stunned sap and men learned to burn smudge pots; 1951, when rain refused to sign the season's ledger; 1983, when orchards cracked under ice and acreage moved west. At dawn today, a picker lifts a ladder, the fruit's pores exhale, and the air carries both blossom and warning. Between his breaths, markets have shifted—tariffs lowered, trucking faster, storms warmer but sharper at the edge. The record shows a rhythm: bounty, bruise, recalculation. After each blow, growers swapped varieties, buried shallow lines deeper, laid wind machines against northers. County agents wrote new pamphlets; banks revised their patience. The harvest, if it arrives, is thus never singular; it is a sum of rehearsals. This is why the co-op's proposal—diversify blocks, insure frost nights jointly, share real-time canopy data—reads less like a gamble than an echo. History does not circle back; it spirals, and every turn tightens the need for coordination. By setting one morning's pick beside a ledger of decades, the case makes itself: resilience is policy, not luck.

Which choice best explains how the passage's braided chronology supports the author's purpose?

Begin with a street that keeps its heat after sundown. The asphalt drinks noon and, at dusk, returns it to skin and brick. That delayed exhale nudges air conditioners later into the night; compressors pump out more warm air; the neighborhood's thermal baseline rises. Now add lost trees: less shade means the pavement takes more; evapotranspiration shrinks; the air dries; summer storms split around the city center. The drier air suppresses cloud formation locally, which cuts late-day shade further and extends the cycle. At each rung, a choice appears. If roofs gleam, they reflect rather than store; if alleys breathe, permeable surfaces wick water into soil that can cool by release; if canopy grows, the street's energy budget rebalances. But interventions misfire when the dominant bottleneck is misread: paint a roof where trees are absent and wind is blocked, and you blunt only a fraction of the loop. The map, then, is not a checklist but a decision tree: trace the strongest branch of accumulation, and place effort at its base. The purpose is not to name every factor; it is to shepherd the reader from symptom to leverage point.

How does the passage's layered cause-and-effect organization most effectively advance the author's purpose?

Texas drinks from stacked vaults—Ogallala, Edwards, Carrizo-Wilcox—each with its own cadence and constituency. The problem is not merely scarcity, but mismatch: withdrawals spike at household taps, municipal pipes leak invisibly, and basins wait years to feel last month's rain. So the argument proceeds by scale. At the sink, a tiered budget rewards habits, not purchases; high-use months trigger a surcharge that funds low-cost retrofits for neighbors. At the city level, sensors find silent losses; contracts index utility bonuses to measured gallons saved underground, not to projects announced. At the basin, farmers who rest fields during peak draw receive credits redeemable when storms return, and recharge projects position check-dams where geology agrees. After each proposal, a counterweight: how to shield low-income families from punitive pricing; how to verify conserved water without policing showers; how to prevent paper credits from outrunning wet reality. The grid that results—three rows of problems, three columns of answers and cautions—does not promise a silver bullet. It offers instead a choreography in which fairness and feasibility take the same step. Persuasion here depends not on a single grand claim, but on aligning remedies to the scale of harm.

Which option best explains how the passage's matrixed problem–solution structure strengthens its argument?

To audit neighborhood air without a laboratory, work in phases that learn from one another. Phase one, scoping: walk the blocks at dawn and dusk to feel wind corridors, note recurring smells, and sketch likely sources; if rain is imminent, postpone so baselines aren't washed thin. Phase two, instrument rehearsal: charge monitors, let them warm to their own steady readings, and cross-check side by side; if a unit drifts, retire it rather than contaminate a route. Phase three, route design: pair a short, repetitive circuit near suspected sources with a longer transect through residential streets; if traffic surges, flip the order to preserve calm-time readings. Phase four, sampling windows: collect in matched slices across weekdays and weekends; if gusts spike or a grill festival blooms, tag the pass and resample. Phase five, triage and sharing: plot the cleanest day first to define a baseline, then lay the noisy days over it and publish both the map and your methods. Because each phase ends with a checkpoint and a contingency, volunteers see not just what to do, but when to revise. The aim is trustworthy data, and the sequence builds that habit.

How does the passage's phased, conditional sequence best serve its instructional purpose?