Answer to Question 1
Unlike other world regions, Sub-Saharan Africa does not have broad alluvial lowlands that influence patterns of settlement. Rather, most human settlements are widely scattered. Population densities are related to the fertility of the soils; countries with relatively more fertile soils, such as those surrounding the Great Rift Valley (e.g., Rwanda and Burundi) exhibit considerably higher population densities. Other major areas of human settlement are located along coastal locations and the major rivers of the continent.
Answer to Question 2
C
Factors for Tolerance Intervals
Static Stability & Environmental Lapse Rate
Economic Globalization
Environmental Issues
Primary factors affecting blood pressure
Expansion factors for orifice plates