UPCAT Reading Comprehension practice question 19: Which statement best captures the passage's overall point?
Correct answer
A. Urban heat is unevenly distributed, and the districts most exposed to it have the least tree cover.
The passage explains the mechanism, quantifies the benefit, then shows canopy cover tracks income, concluding that the most exposed residents have the least shade.
Heat Islands and the Value of Shade
Two neighborhoods in the same city can differ by as much as five degrees Celsius on the same afternoon. The mechanism is straightforward. Asphalt and concrete absorb solar radiation during the day and release it slowly after sunset, so a district with little vegetation stays hot long into the night. Trees interrupt the cycle twice: their canopies block radiation before it reaches the pavement, and the water they release through their leaves carries heat away as it evaporates.
Measurements across several tropical cities suggest that raising canopy cover from ten percent to thirty percent of a district's surface lowers peak afternoon temperature by roughly two to three degrees. The effect on nighttime temperature is smaller but more consequential for health, since sustained overnight heat is what drives hospital admissions during heat waves.
Canopy cover, however, tracks income closely. Wealthier districts were often planted decades earlier, and their trees have had time to mature; newer settlements built at higher density have narrow roads with no space reserved for planting. The result is that the residents most exposed to extreme heat, and least able to afford air conditioning, live where there is least shade.
The question
Which statement best captures the passage's overall point?
- Option A: Urban heat is unevenly distributed, and the districts most exposed to it have the least tree cover.Correct
- Option B: Concrete and asphalt should be replaced with more reflective materials.
- Option C: Air conditioning is the most effective response to urban heat.
- Option D: Tree planting is more difficult in tropical cities than in temperate ones.
Why A is correct
The passage explains the mechanism, quantifies the benefit, then shows canopy cover tracks income, concluding that the most exposed residents have the least shade.