What are the basic activities in each of the four economic activity level?

Data courtesy of the un development programme 2006-2008 and world bank 2009 the chart above compares measures of development using the hdi and gdp. why might turkey rank lower in the hdi indicator even though it has a high gdp?

Trade routes emerged along which coast when arab and indian traders from around the indian ocean mixed with the bantu people from africa's interior? a. swahili coast b. guinea coast c. drakensberg coast d. namib coast

Which layer surrounds the center of the earth? a: crust b: core c: mantle