Comment on the following statements in terms of the properties of the elements mentioned.

(a) For many decades, tungsten was used to make filaments in incandescent light bulbs. Tungsten is used in preference to copper even though the electrical resistivity of tungsten is greater than that of copper.

(b) Incandescent light bulbs are filled with a gas such as Ar or Xe.

(c) A halogen lamp contains a tungsten filament in a quartz bulb filled with halogen gas. The halogen is Br₂ or I₂, but not F₂ or Cl₂. The lifetime of the filament is prolonged with respect to that in an incandescent bulb.