Domesticated herd animals were first integrated into agriculture when they were used A. to assist hunters.
B. for their meat and milk.
C. to transport harvested crops.
D. for their fur and skins.
E. to prepare land for planting.
THIS IS FOR AP HUMAN GEOGRAPHY

answer; i believe the correct answer is ; large pieces of pangaea drifted in different directions over millions of years;

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.