Glaciers
form when snow stays in the same place for a long time
cover about 5% of earth's land
can only exist in cold regions near the poles
contain about 70% of earth's saltwater

Read the article titled "trans-saharan migration routes to north africa and the eu: historical roots and current trends." why do tens of thousands of sub-saharan africans try to cross the mediterranean each year? how are these refugees commonly portrayed? (site 1)