1 .		The Tifernine Dunes form the southernmost part of the Grand Erg Oriental, one of the most desolate parts of the Sahara. The nearest oasis is 100 kilometers (62 miles) away. The structures within the dune field are highlighted by the evening sun, giving a better perspective on their height and morphology. What type of dunes are they, and from what direction does the dominant wind blow? Rain is extremely rare in this part of the Sahara today, and may fall only once every decade or two. What evidence can you see in the photograph indicating that the climate was wetter in the past? [Source]   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
2 .		The flow of the Colorado River is controlled by a series of dams which have created several lakes along its length. The Colorado has been so heavily engineered because it provides an important source of water and hydroelectric power for the arid western United States. Since the early 1960s, the Glen Canyon Dam has altered the flow of the Colorado River through the Grand Canyon. Ecologists have been concerned about the impact of this dam on the ecosystem of the Grand Canyon. What are some of the observed changes in the Grand Canyon that have occurred as a result of the construction of this dam? In March and April 1996 the U.S. Bureau of Reclamation initiated a controlled flooding of the river in an attempt to restore the ecology and animal habitats of the Grand Canyon. What was the outcome of this effort? Was it successful? Use HotBot, the search engines on our GeoSearch page and the following resources to answer these questions. Grand Canyon Studies: Using Ocean-Research Techniques to Study a River System Grand Canyon National Park: Official Park Information   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.