Which one of these commands does not use Target Body and Tool Body selections?

The command you selected, Combine, is indeed the correct choice because it does not require separate Target Body and Tool Body selections during its operation. The Combine command is used to merge, subtract, or intersect solids, effectively altering the geometry of the Target Body based on the Tool Body selected.

In contrast, commands like Sew, Emboss Body, and Trim and Extend explicitly involve the concept of targeting a body to modify it, using another body (the Tool Body) to define how the modification occurs. For instance, Sew is utilized for combining several surfaces into a single body, requiring a selection of the surfaces involved. Emboss Body allows you to add features to a body based on the geometry of another part, while Trim and Extend manipulates the edges of a body by referencing a selected Tool Body. These commands inherently depend on making specific selections for both the Target and Tool Bodies to achieve their intended functionalities.