Chapter 20

Section 1

1. The shifting of tectonic plates has caused lakes and rivers to widen, and has caused the formation of several land rifts, such as the Great Rift Valley.

2. A land form known as a delta splits both the Niger and the Zambezi River into two parts. The ground outside of Lake Chad swallows the moisture around it, which is shrinking the lake

Creative Writing: Mines for minerals in regions below the Sahara have several problems that include its topography and its water systems. Areas of large rifts, high mountains, and vast deserts make less than ideal mining camps because of their unstable ground and harsh conditions. Rivers that contain rapids, waterfalls, and those that empty into large bodies of water will not be able to be mined because they will not be able to shut off the river completely.

Section 2

1. Three factors that affect the climate of Africa are ocean currents, prevailing wind patterns, and elevation.

2. Three main kindas of climates in this region are tropical wet, tropical dry, and steppe, and in these climates are dense forests, grasslands and scattered trees, and shrubs and acacia trees, respectively.

Creative Writing: The vast plains of the Serengeti Plains of the central African region and the Great Plains of the central North American region are not unlike one another. Both regions are teeming with wildlife are large amounts of simple grasses and the scattered areas of trees along with a few systems of water, yet not very much fertile soil.