Briefly explain the causes of glaciation and the processes that cause glaciers to grow. Briefly explain how changes in sea level and evidence of past marine life are related.

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6. For glaciation to begin, something needs to cause Earth's temperatures to drop. If this happens, snow that falls on the polar ice caps doesn't melt, and glaciers grow. As snow and ice reflect sunlight, the Earth's temperature is reduced even further, causing glaciers to continue growing.

7. Sea level changes cause marine transgressions and regressions. During a marine transgression, the shoreline moves inland, leaving sedimentary deposits that contain fossils. The shoreline retreats during a marine regression, leaving behind the deposited sediments.

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.

a is the answer i believe.