3. Free electives: Free electives are courses in addition to the Core Curriculum and major requirements sufficient to reach a minimum of 120 credit hours for graduation. Students may graduate with more but not less than 120 credit hours.
The four major North American deserts of this type are the Chihuahuan, Sonoran, Mojave and Great Basin. Others outside the U.S. include the Southern Asian realm, Neotropical (South and Central America), Ethiopian (Africa) and Australian. The seasons are generally warm throughout the year and very hot in the summer.
Yet more than one billion people, one-sixth of the Earth's population, actually live in desert regions. Deserts cover more than one fifth of the Earth's land, and they are found on every continent. A place that receives less than 10 inches (25 centimeters) of rain per year is considered a desert.Deserts are part of a wider classification of regions called drylands..thers are mountainous. Only about 10 percent of deserts are covered by sand dunes. The driest deserts get less than half an inch (one centimeter) of precipitation each year, and that is from condensed fog not rain. Desert animals have adapted ways to help them keep cool and use less water.