The republic of south africa exports edible fruits and nuts into the common market known as the european union, and imports from the european union other products which south africa could produce but at a higher cost than what it costs the europeans to produce. this practice follows the theory of

Comparative Advantage (David Ricardo classical theory of international trade)

Explanation:

In an economy in autarky (does not trade with other countries) only goods produced in the country are consumed, while in an economy that trades internationally, excess production can be traded of a good in which there is comparative advantage (better conditions of production of a good) for other goods that are more expensive due to infrastructure issues and other variables to produce in the country.

This theory was developed by David Ricardo (English economist), who founded international trade under the assumption that countries improve their profit and consumption by trading internationally.

imperial crisis leads to civil war.

roman forces withdraw from britain as goths attack rome.

odoacer topples romulus augustus

huns attack the empire and drive german peoples ahead of them.

the earth’s crust is broken into separate pieces called tectonic plates (fig. 7.14). recall that the crust is the solid, rocky, outer shell of the planet. it is composed of two distinctly different types of material: the less-dense continental crust and the more-dense oceanic crust. both types of crust rest atop solid, upper mantle material. the upper mantle, in turn, floats on a denser layer of lower mantle that is much like thick molten tar.

each tectonic plate is free-floating and can move independently. earthquakes and volcanoes are the direct result of the movement of tectonic plates at fault lines. the term fault is used to describe the boundary between tectonic plates. most of the earthquakes and volcanoes around the pacific ocean basin—a pattern known as the “ring of fire”—are due to the movement of tectonic plates in this region. other observable results of short-term plate movement include the gradual widening of the great rift lakes in eastern africa and the rising of the himalayan mountain range. the motion of plates can be described in four general patterns:

collision: when two continental plates are shoved together

subduction: when one plate plunges beneath another (fig. 7.15)

spreading: when two plates are pushed apart (fig. 7.15)

transform faulting: when two plates slide past each other (fig. 7.15)