transporting materials through a plant is a kind of function
transport_of_people is conveying_materials. moving_earth is conveying_materials. smuggling is conveying_materials. material_transporter is transportation_device. electricity is useful_way_to_transport_energy. transport is diffusion. cargo_ship is material_transporter. transport_container is conveyance. transport_of_mail is conveying_materials. export_import is conveying_materials.