Preview the following selection. Then read it and answer the questions.
Chicago's early boosters bragged that nature had given their city everything it needed to be great: a river running through it and a harbor on busy Lake Michigan. What the boosters did not say was that the river was short and shallow-"a sluggish, slimy stream, too lazy to cleanse itself," a visitor noted-or that sand often blocked the entrance to the harbor. To make Chicago work, humans would have to intrude upon nature to change the river and clear the harbor, creating out of "first nature" a "second nature," as environmental historian William Cronon put it.
They did just that. In remaking "first nature," government-financed engineers deepened the river and erected barriers to the sand. Then they turned to another of nature's challenges-the thick, cloying mud that plagued Chicago whenever it rained. Using muscle and jacks, they simply lifted the city a dozen feet out of the mud, producing "second nature" once again.
The city, now raised to working level, next turned to the railroads, the dazzling technological innovation that mastered nature to transform 19th century life. Unlike rivers and canals, railroads could go virtually anywhere, and many of them wound up going to Chicago, which became the main terminal point for trains heading east and west. It was "natural" for them to do so. Chicagoans believed, and they certainly seemed right. By the early 1890s, one-twenty-fifth of all railroad mileage in the world terminated in Chicago.
They terminated there, in part, to drop off and pick up the city's most recent tinkering with nature, the pigs and cows destined to feed the country's growing population. A city that exuded life and growth, Chicago became filled with death, famed for "the Chicago style" of killing pigs. It was, said British writer Rudyard Kipling after visiting the city, a "death factory."
To organize the killing, the giant Union Stockyards opened on Christmas Day, 1865, built just south of the city on a marshy prairie prone to flooding. "Second nature" again took charge. Thirty miles of pipes drained the water from the prairie. The water, carrying with it waste from the stockyards, discharged into the Chicago River, which soon smelled horrific and carried disease. Within the stockyards, 10 miles of troughs dispersed corn and hay among 2000 pens, to feed at any one time 21,000 head of cattle, 75,000 pigs, and 22,000 sheep. Sidetracks allowed animals to be brought into the yards for slaughter and then carried the resulting products out to distant markets. (Taken from America Past and Present, Divine, Breen, Fredrickson, Williams, Gross and Brands, 7th Ed, New York: Pearson, 2005, pgs 526-527)
"A sluggish, slimy stream, too lazy to cleanse itself" is an example of which of the following?