The housewife, switching on her electric kettle to make another cup of tea, gave no thought to the immense complex of operations that made that simple action possible: the building and maintenance of the power station that produced the electricity, the mining of coal or pumping of oil to fuel the generators, the laying of miles of cable to carry the current to her house, the digging and smelting and milling of ore or bauxite into sheets of steel or aluminium, the cutting and pressing and welding of the metal into the kettle's shell, spout and handle, the assembling of these parts with scores of other components - coils, screws, nuts, bolts, washers, rivets, wires, springs, rubber insulation, plastic trimmings; then the packaging of the kettle, the advertising of the kettle, the marketing of the kettle to wholesale and retail outlets, the transportation of the kettle to warehouses and shops, the calculation of its price, and the distribution of its added value between all the myriad people and agencies concerned in its production.
Which sector is the underlined sentence part of?
