All of these are true about GMA (MIG) welding EXCEPT that: O both the base metal and electrode are melted.
O shielding gas protects the well, tiom contamination.
O heat is produced using a short electric arc.
the welding gun liner regulates the shielding gas.

the welding gun liner regulates the shielding gas.

Explanation:

The purpose of the welding gun liner is to properly position the welding wire from the wire feeder till it gets to the nozzle or contact tip of the gun. Regulation of the shielding gas depends on factors such as the speed, current, and type of gas being used. In gas metal arc welding, an electric arc is used to generate heat which melts both the electrode and the workpiece or base metal.

The electric arc produced is shielded from contamination by the shielding gas. The heat generated by the short electric arc is low.

visit this site

explanation: