Name the major desert located in the southwestern United States.

The Mojave Desert is indeed a major desert located in the southwestern United States. It spans across several states, primarily California, Nevada, and Arizona. This desert is characterized by its unique ecosystem, which includes a variety of plants and animals adapted to its arid conditions, such as the iconic Joshua tree. The Mojave is also known for its varying elevations, which range from below sea level to mountainous regions, contributing to its distinct climate and environment.

In contrast, while the Sahara Desert is the largest hot desert in the world, it is located in North Africa and not in the United States. The Great Basin Desert, although significant, is primarily in Nevada and is considered a cold desert, distinct from the Mojave in terms of climate and ecology. Lastly, the Sonoran Desert is another major desert in the southwestern US, covering parts of California and Arizona, but it is separate from the Mojave in both location and environmental characteristics. Thus, while the Sonoran Desert is important, the Mojave is specifically recognized for its own distinctive features and significance in the region.