These periodic changes on Earth are a result of the five major that have occurred throughout Earth's history.

there are conflicting perceptions. what cannot be denied is that despite a long history of discrimination, they finally chose to bow out in grace and handed over power to the majority. it was a painful experience for them to part with their prerogatives and some chose to leave the country. however, they did decide to bite the bullet and go through the process with minimum obstructions.

presently, whites are still a force to reckon with. they are well educated, have technical and business expertise, they understand imperatives of good governance and are responsible for keeping south africa connected with developed countries. despite a bitter history, they are useful team members of the south african team.

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)

sir frederic attributed inaccuracies to schemas. memory reconstruction is one part actual events and one part personal schema, which can result in inaccuracies when memories are reconstructed.

answer; /// charles darwin;