What commodities were traded using the silk road? silk silk, gold, ivory, animals, and plants precious metals grains

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 causes heat transfer in fluids

What is the connection between a metalloid and a semiconductor