What does the Union tool retain when combining multiple datasets?

The Union tool in ArcGIS Pro is designed to combine multiple datasets while preserving all features from the input datasets. This means that when you apply the Union operation, every feature from each input layer is retained in the output dataset regardless of whether the features overlap or not. This is particularly useful when you want to analyze and visualize a comprehensive set of features, ensuring that no data is lost during the merging process.

By retaining all features from input datasets, the Union tool allows users to perform analyses that consider every aspect of the input data, which can provide deeper insights, especially in complex geographic scenarios where multiple layers need to be integrated. Thus, the correct choice effectively highlights the main functionality of the Union tool in delivering a complete and inclusive dataset from the combined inputs.