Interactive Reading

Read the passage and answer the question.

In the 1800s, ice was a global business. Long before refrigerators existed, workers in cold regions sawed huge blocks from frozen lakes in winter and packed them in sawdust, which slowed melting. Ships carried this ice thousands of miles to warm cities, where it cooled food and drinks through the summer. Remarkably, enough survived the long journey to make the trade profitable. The industry collapsed only when machines that could manufacture ice anywhere became cheap and reliable. What had once been a precious natural resource, harvested and shipped at great effort, suddenly became something any factory could produce on demand, ending a trade that had lasted generations.