While discussing pressure gauge sets, technician a says manifold gauges are only
available in mechanical style. technician b says that when using the gauge set, make
sure both service knobs are in the open position before connecting them to a system. who is correct?

explanation:  

an electrode is a metal whose surface serves as the location where oxidation-reduction equilibrium is established between the metal and what is in the solution.

An artesian well is simply a well that doesn't require a pump to bring water to the surface; this occurs when there is enough pressure in the aquifer. The pressure forces the water to the surface without any sort of assistance