The migration pattern shown on the  map was most likely facilitated by   — a the warming of the Pacific Ocean due to climate change b a land connection between Asia and North America c an isthmus connecting North America and South America d the spread of the Canadian glaciers across North America

b a land connection between Asia and North America

Explanation:

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.

these include the fossil fuels, oil, natural gas, and coal and nuclear energy. hope this ! ^.^

-ella