Which conditions are necessary for natural selection?

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)

What are three similarities between medc countries and ledc countries?

What is one early technological advance that shaped culture? a the use of fire b the discovery of arable land c family units. d migration