What metric is commonly used to measure how many people live in a specific area, often expressed as individuals per square kilometer?

The correct answer is population density, which specifically refers to the measure of how many individuals inhabit a particular area, typically represented in terms of individuals per square kilometer or per square mile. This metric provides valuable insights into how crowded or spacious an area is, influencing urban planning, resource allocation, and infrastructure development.

In contrast, population growth refers to the increase in the number of individuals in a population over time, rather than the spatial measurement of how many reside in an area. Population distribution, on the other hand, describes how individuals are spread across a particular region but doesn't provide a measure per unit area. Urban sprawl pertains to the expansion of urban areas into previously undeveloped land, which is related to urban development patterns but does not directly measure the density of the population in an area. Thus, population density is the most appropriate metric for this context.