Question 1 of 36
Cooling Down the Hottest Blocks
(1) On a July afternoon in many American cities, the temperature on one block can be ten degrees higher than the temperature a mile away. Scientists call this the urban heat island effect. It is not just uncomfortable. Extreme heat sends thousands of people to emergency rooms each summer, and it is especially dangerous for older adults, outdoor workers, and people who cannot afford air conditioning.
(2) The causes are mostly built into the city itself. Dark asphalt and rooftops absorb sunlight during the day and release that heat slowly at night, so neighborhoods never fully cool off. Cars, air conditioners, and factories add even more heat. Meanwhile, blocks with few trees lose the natural cooling that shade and leaves provide. As a result, the hottest neighborhoods are often the ones with the most pavement and the least green space.
(3) Consider the experience of Marisol Vega, a home health aide in the fictional city of Eastport. She walks between her clients' apartments all day. "By noon, the sidewalk feels like a stove," she says. On her route, there is almost no shade for six blocks. She now carries two bottles of water and plans her visits so that she is indoors during the hottest hours.
(4) Cities have begun to fight back with several strategies. The first is planting trees. A mature street tree can shade a sidewalk and cool the air around it as water evaporates from its leaves. A second strategy is "cool roofs," which are painted white or coated with reflective material so they bounce sunlight away instead of absorbing it. A third is replacing some asphalt with lighter pavement or with grass and plants.
(5) None of these solutions is instant. A young tree may need fifteen years to grow a wide canopy, and it needs watering and care in its first few summers. Cool roofs cost money, although they can lower a building's cooling bills. For these reasons, some planners argue that cities should start with the blocks that are hottest and have the most vulnerable residents.
(6) The heat island problem took decades of building to create, and it will take years to undo. But each shaded sidewalk and each reflective roof makes a measurable difference for the people who live and work below.
Which statement best describes the overall structure of the passage?
Hint
Look at what each paragraph does in order: first what is wrong, then why, then what is being done about it.
Step-by-step solution
Trace the job of each paragraph. Paragraph 1 names a problem: "Scientists call this the urban heat island effect" and explains that extreme heat "sends thousands of people to emergency rooms." Paragraph 2 gives the causes: "The causes are mostly built into the city itself." Paragraph 3 shows how the problem affects one worker. Paragraph 4 turns to solutions: "Cities have begun to fight back with several strategies." Paragraph 5 notes limits of those solutions, and paragraph 6 wraps up.
So the passage describes a problem, explains why it happens, and then presents ways to solve it. That is a problem-solution structure (with a cause-effect section inside it).
The correct answer is A.
The other choices name real structures, but not this one. Only one city (a fictional one) is described, so it is not a comparison of cities. There are no dates moving forward in order, so it is not a history. And the author never sets up an opinion just to argue against it.
Tip: For "overall structure" questions, write a two- or three-word label beside each paragraph (problem, causes, example, solutions). The pattern in your labels is the answer.