It is a safety procedure in industries that lock dangerous machines and ensure that there is no operation until maintenance or repairs have been made.
Plates at our planet's surface move because of the intense heat in the Earth's core that causes molten rock in the mantle layer to move. It moves in a pattern called a convection cell that forms when warm material rises, cools, and eventually sink down. As the cooled material sinks down, it is warmed and rises again
it is a disease, commonly found in young children.
