Reading Standards for Informational Text > Language, Sound, and Meaning (CCSS.RI.6.2) Practice Test

In cities packed with buildings and pavement, trees do more than look nice. Their shade can lower summer temperatures on streets by several degrees, making walks and bus stops safer and more comfortable. Leaves capture air pollutants and produce oxygen, improving the air people breathe. Roots soak up stormwater that might otherwise flood basements and overwhelm drains. Studies also link time around trees to lower stress and better concentration for students. Yet the benefits are not spread evenly. Neighborhoods that lost tree cover to wide roads or redlining policies often feel hotter and have worse air. Planting new trees helps, but saplings need years of care, including watering during dry spells and protection from damage. City leaders can plan for the future by choosing species that tolerate heat and planting them where people spend time—near schools, sidewalks, and bus routes. When residents, volunteers, and local governments work together, a small patch of shade today can grow into a healthier block tomorrow. In short, investing in urban trees makes cities healthier and more livable.

During a deadly cholera outbreak in London in 1854, physician John Snow suspected the disease was spreading through contaminated water, not "bad air." To test his idea, he walked the crowded streets around Broad Street and marked every cholera death on a map. A clear pattern appeared: most cases clustered near a single public pump. Snow interviewed families and learned that even people who lived far away had become sick after drinking water from that pump. He presented his findings to local officials, who removed the pump's handle. New cases quickly dropped. Snow could not see the germs themselves—microscopes were limited at the time—but his careful use of data convinced many people to rethink how disease traveled. In the years that followed, the city improved sewers and water supplies, and other communities adopted similar methods. Snow's investigation showed that gathering evidence, looking for patterns, and acting on the results can save lives. This approach marked a turning point in public health.