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.
Due to the global pattern of air circulation and the relation to the atmosphere, most deserts are found within a belt centered on the 30Â° North and 30Â° South latitude lines. These regions are characterized by having a great deal of sunlight, minimal rain and high levels of evaporation.