Before movable-type printing became widespread in Europe, books were reproduced mainly by hand copying or by block-printing methods. These processes could produce attractive texts, but they were slow and labor-intensive. In the mid-fifteenth century, European printers began using systems that combined reusable metal type, oil-based ink, and mechanical presses. The innovation did not make books instantly cheap or universally available, yet it greatly increased the number of copies that could be produced from a prepared text. Printing also changed the economics of textual production. Printers had strong incentives to sell many copies of the same work, which encouraged larger distribution networks and more standardized editions. However, standardization was incomplete: printers corrected errors during production, reused type, and sometimes altered texts for local markets. The growth of printing supported the circulation of religious, scientific, legal, and literary works, but historians caution against treating the printing press as a single cause of later social change. Literacy rates, trade networks, political institutions, and demand for particular kinds of knowledge also shaped how printed material was produced and used.
Why do historians caution against treating printing as the single cause of later social change?

Cities are often warmer than surrounding rural areas, a pattern known as the urban heat island effect. Several features of the built environment contribute to this difference. Dark surfaces such as asphalt absorb a large portion of incoming solar energy during the day and release some of that stored heat after sunset. Buildings can also reduce air circulation, while vehicles and air-conditioning systems add waste heat to the environment. Vegetation tends to moderate temperatures because leaves provide shade and because plants release water vapor through transpiration. For this reason, urban planners increasingly use trees, parks, reflective roofs, and permeable surfaces as cooling strategies. These interventions do not affect every neighborhood equally. Their effectiveness depends on local climate, building density, available water, and maintenance. Researchers therefore caution against assuming that a single strategy will produce the same result everywhere. Instead, they recommend combining temperature measurements with neighborhood-level data before selecting interventions. The urban heat island effect is important not only because it influences comfort but also because high nighttime temperatures can increase health risks during heat waves by limiting the body’s opportunity to recover from daytime heat.
Select TWO cooling strategies mentioned in the passage.

Migration allows animals to exploit resources that vary across space and time. Birds may travel between breeding and wintering grounds, while some fish move between freshwater and marine environments. The benefits of migration can be substantial, but so are the costs. Long journeys require energy and may expose animals to predators, storms, unfamiliar habitats, and human-made obstacles. Migratory behavior is guided by a combination of inherited tendencies and environmental cues. Day length, temperature, food availability, and social information can all influence when movement begins. Navigation mechanisms differ among species. Some animals use the position of the Sun or stars, while others detect Earth’s magnetic field or recognize landmarks. Because migration depends on conditions at multiple locations, habitat loss at a single stopover site can affect populations that spend most of the year elsewhere. Conservation biologists therefore increasingly emphasize the protection of connected networks of habitats rather than isolated reserves. Climate change adds another complication by altering the timing of seasonal events. If insects emerge earlier in spring but migratory birds do not adjust their arrival time, the birds may miss a critical food peak.
What mismatch does the passage describe as a possible climate-change problem?

Migration allows animals to exploit resources that vary across space and time. Birds may travel between breeding and wintering grounds, while some fish move between freshwater and marine environments. The benefits of migration can be substantial, but so are the costs. Long journeys require energy and may expose animals to predators, storms, unfamiliar habitats, and human-made obstacles. Migratory behavior is guided by a combination of inherited tendencies and environmental cues. Day length, temperature, food availability, and social information can all influence when movement begins. Navigation mechanisms differ among species. Some animals use the position of the Sun or stars, while others detect Earth’s magnetic field or recognize landmarks. Because migration depends on conditions at multiple locations, habitat loss at a single stopover site can affect populations that spend most of the year elsewhere. Conservation biologists therefore increasingly emphasize the protection of connected networks of habitats rather than isolated reserves. Climate change adds another complication by altering the timing of seasonal events. If insects emerge earlier in spring but migratory birds do not adjust their arrival time, the birds may miss a critical food peak.
Which factor is mentioned as a cue that can influence migration timing?

Before movable-type printing became widespread in Europe, books were reproduced mainly by hand copying or by block-printing methods. These processes could produce attractive texts, but they were slow and labor-intensive. In the mid-fifteenth century, European printers began using systems that combined reusable metal type, oil-based ink, and mechanical presses. The innovation did not make books instantly cheap or universally available, yet it greatly increased the number of copies that could be produced from a prepared text. Printing also changed the economics of textual production. Printers had strong incentives to sell many copies of the same work, which encouraged larger distribution networks and more standardized editions. However, standardization was incomplete: printers corrected errors during production, reused type, and sometimes altered texts for local markets. The growth of printing supported the circulation of religious, scientific, legal, and literary works, but historians caution against treating the printing press as a single cause of later social change. Literacy rates, trade networks, political institutions, and demand for particular kinds of knowledge also shaped how printed material was produced and used.
The word “incentives” is closest in meaning to: