Question 110·Medium·Inferences
Many municipalities have replaced their sodium-vapor streetlights with light-emitting diode (LED) fixtures, expecting to save money and reduce light pollution. In one midwestern city, researchers tracked energy use, skyglow, insect activity, and bird collisions before and after a pilot conversion from sodium lamps to dimmable, cool-white LEDs. Over two years, the city used 35 percent less electricity, but traps beneath the cool-white LEDs captured roughly three times as many insects as before, and springtime collisions of migrating birds with glass bus shelters rose by about 15 percent. Midway through the pilot, the city switched the same corridors to warmer LEDs and added full cut-off shields while keeping the dimming schedule; the increased skyglow and wildlife impacts then dropped close to pre-conversion levels, while energy savings persisted. Based on these findings, the research team suggests that future lighting upgrades in the city should _____
Which choice most logically completes the text?
For “Most logically completes the text” questions that follow a research summary, restate the key findings (what changed after each intervention) and then pick the recommendation that best matches the configuration that produced the best overall outcome. Eliminate options that ignore major results, throw away a demonstrated benefit without need, or claim the results were unclear when the passage describes a clear pattern.
Hints
Focus on the phrase before the blank
Look carefully at the sentence that leads into the blank: it asks what the research team suggests "based on these findings." Make sure you understand what "these findings" are.
Compare the two lighting setups tested
Compare the outcomes from the initial LED conversion to the outcomes after the mid-pilot adjustment to the LED setup (changes to the light’s color/temperature and the use of shielding). Track energy use, skyglow, and wildlife impacts in each phase.
Decide what a reasonable recommendation should balance
Should the researchers ignore ecological impacts to save energy, ignore energy savings to protect wildlife, or try to get both benefits at once? Eliminate any answer that clearly conflicts with the results described.
Check whether the study seems conclusive or not
Does the passage describe clear changes linked to each setup, or does it say the results were unclear or mixed? Use that to judge answers that talk about reinstalling old lamps or delaying decisions.
Step-by-step Explanation
Identify the purpose of the blank
The blank comes after a description of a pilot project and its results. The phrase "Based on these findings, the research team suggests that future lighting upgrades in the city should" tells you that the correct answer must be a recommendation that follows logically from the specific evidence just described.
Summarize the key findings
The passage gives two main results:
- After switching from sodium lamps to cool-white LEDs, the city used 35% less electricity, but insect captures tripled and bird collisions increased about 15%.
- Midway through, the city changed to warmer LEDs and added full cut-off shields (with the same dimming schedule). Skyglow and wildlife impacts dropped close to pre-conversion levels, and the energy savings continued.
Determine what a logical recommendation must do
A reasonable recommendation based on these results should keep the energy savings from LEDs while avoiding the increased skyglow and wildlife impacts associated with the initial cool-white, unshielded setup.
Match the recommendation to the successful setup
The only choice that mirrors what worked in the second phase of the pilot—reduced skyglow and wildlife impacts while maintaining energy savings—is:
install warmer, fully shielded LEDs to cut skyglow and wildlife impacts while keeping the energy savings.