How did human societies begin to change at the conclusion of the last Ice Age? A. War between the tribes occurred

B. Hunting techniques improved

C. Permanent settlements formed

D. The first cave paintings appeared

i believe it's A-war between the tribes occurred

Explanation:

i hope this helps you, sorry if it doesn't.

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.