Which type of region is defined by measurable natural features?

The correct choice is grounded in the characteristics of ecological regions, which are delineated based on specific natural features and ecosystems. These regions are defined by measurable criteria such as climate, vegetation, soil types, and animal habitats. This focus on quantifiable environmental aspects means that ecological regions provide a scientific basis for understanding different areas of the Earth in terms of their natural landscape and biological communities.

In contrast, other types of regions do not focus primarily on measurable natural features. For instance, formal regions are characterized by uniformity in one or more physical or cultural traits but may not be limited to just natural features. Functional regions are defined by their connection and interaction within a system, such as transportation routes or economic service areas rather than strict natural boundaries. Vernacular regions are based on perceptions and cultural identities, often shaped by subjective feelings and experiences, rather than defined by measurable physical characteristics. Thus, ecological regions stand out for their reliance on specific, quantifiable natural features.