Which density measure differs most between Egypt and Ethiopia? What might account for this difference?

Density options:
Arithmetic
Physiological
Agricultural

Who owned most of the resources in a market or capitalistic economy? in a socialist or command economy? what determines ownership in a traditional economy. (economies)

What is a small water source like a stream or brook?

Witch of the following volcano hazards is made up of rocky particles about the size of a grain of sand