What command is used to create a connected sequence of line and arc segments in AutoCAD?

The command that is used to create a connected sequence of line and arc segments in AutoCAD is the POLYLINE command. This command allows the user to draw a series of connected segments as a single object, which can include both straight lines and arcs. It simplifies the drawing process as you can create complex shapes without needing to join individual line and arc entities later.

The POLYLINE command creates a single entity that can be easily edited as a whole, making it particularly useful for creating shapes like paths, boundaries, and other connected forms. In contrast, other commands like LINE and ARCLINE create individual segments that require additional steps to combine into a single object, leading to a more complex editing process.