By 1900, the population in New York City, Chicago, and Philadelphia had each grown to exceed?

By 1900, the population in New York City, Chicago, and Philadelphia had each grown to exceed one million people.

Explanation:

Due to the positive impact of industrialization, the population of urban centers in America increased greatly. In 1870, only two cities in America had populations that were more than half a million; by 1900, the number of cities that had populations higher than half a million, increased to six. The population in each of three cities (out of the six) - Chicago, New York, and Philadelphia-had grown to exceed one million people.