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.
Evaporation rates regularly exceed rainfall rates. Sometimes rain starts falling and evaporates before reaching the ground. Rainfall is lowest on the Atacama Desert of Chile, where it averages less than 1.5 cm. Some years are even rainless. Inland Sahara also receives less than 1.5 cm a year. Rainfall in American deserts is higher  almost 28 cm a year.
Location of Deserts. The location of deserts is dependent on two factors, latitude and global wind patterns. Most deserts are located between 15' and 35' latitude, both north and south of the equator. In terms of global wind patterns, most deserts are located within the Southeastern and Northeastern trade winds belt.