Which term refers to a manageable unit for studying Earth's human and natural environments?

The term that refers to a manageable unit for studying Earth's human and natural environments is "region." This term encompasses various geographical characteristics and allows for the classification and analysis of areas based on similar natural features or human activities, such as culture, economy, and political boundaries.

Regions can be defined by specific criteria, such as physical geography (mountains, rivers), human attributes (language, religion), or economic activities (agriculture, industry). By studying regions, researchers and students can gain a comprehensive understanding of how different environments interact and the impacts of human activities on the earth's systems.

In contrast, a "zone" typically refers to an area defined for specific purposes, such as economic or ecological zones, but may not provide the comprehensive data necessary for studying both human and natural aspects simultaneously. A "sector" usually pertains to a distinct part of a larger system, often in economic or technological contexts, while "area" tends to be a more general term and does not specifically imply the characteristics that define a region in the context of human and environmental studies.