Choose the correct options.

In 1802 a\(n\) ... physiсist discovered the electric arc phenomenon. ... years later, a Russian ... N.Bernardos invented a method to connect 2 metal pieces with welding.
Welding ... to be a very long and tough process. Unlike the welders of the past, modern professionals use ... equipment. Students learn to weld using ... reality simulation. A modern welder must also be a ... to program the welding robots.