The earth's internal process which drives seafloor spreading is

Seafloor spreading is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge.

i also have the same question.

the first phase of the government’s plan for settlement was building the transcontinental railroad. the railroad provided a way to bring settlers and manufactured goods west and ship their agricultural and mining produce east. the transcontinental railroad was an essential artery for rapid development of the frontier.

the second phase of the government’s plan was a liberal land distribution policy that made it possible for many people to homestead. with these two key elements—transportation and cheap land—the government rapidly achieved its goal of persuading people to move west, settle on farms, and push back the frontier.