Which statement is true regarding the coordinate system of geodatabases?

The statement that all feature classes must share the same coordinate system is accurate in the context of feature datasets within a geodatabase. When working with feature datasets, it is essential that all feature classes contained within that dataset utilize the same coordinate system. This uniformity is necessary for proper spatial analysis and data integrity, as differing coordinate systems could lead to misalignment of spatial features, rendering analyses ineffective or inaccurate.

In contrast, while it is true that individual feature classes can reside in different coordinate systems if they are not part of a feature dataset, when incorporated into a feature dataset, they must conform to a single, consistent coordinate system. This requirement ensures that operations such as overlays, proximity analysis, and other spatial functions can be executed seamlessly without discrepancies caused by varying spatial references.

In summary, the necessity for all feature classes within a feature dataset to share the same coordinate system is a fundamental principle of geospatial data management, promoting coherence and reliability in spatial operations.