What is HDI? its concept

Which summarizes the relationship between density of an element and its distribution in earth? a. the greater an element’s density, the greater the amount of it found in the crust. b. the denser an elements is, the smaller the amount of it earth core. c. the greater an elements density, the smaller the amount of it’s found in the crust

For one week be an inventor and write down ideas for products or services that you think should be produced

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)