What best describes Arc Welding?

Arc welding is best described as a method of joining metals using electricity. This process involves generating an electric arc between an electrode and the base material, which produces enough heat to melt the metals at the joint. As the molten metal cools, it solidifies to create a strong bond between the pieces being joined.

In the context of the other choices, cutting metal with lasers involves a different technology that focuses on concentrating light energy to sever materials, which is distinct from the welding process. The technique for molding plastic materials pertains to plastic fabrication rather than metal joining, while heating metals without melting typically refers to processes like brazing or soldering and does not involve the fusion characteristic of welding. Thus, the choice that accurately captures the essence of arc welding is the one that highlights its function as an electrical method for fusing metals.