Much of southern Arizona lies in the Sonoran Desert. There's hardly any surface water, but the warm climate attracts a growing population, and the region's cities have ballooned. Here, you can see suburbs of Tucson sprawl to the foot of the Catalina Mountains; intense watering keeps the golf courses green. How is this sustainable?

1. crust 1 the metallic layer at the earth's center 2. inner core 3 the firm layer between the crust and the asthenosphere 3. lower mantle 2 the layer surrounding the inner core 4. asthenosphere 4 the semi-solid layer between the top layer and the upper mantle 5. upper mantle 5 the layer between the asthenosphere and lower mantle 6. top layer 6 the earth's outermost layer 7. outer core 7 the hottest part of the mantle

Read the article about the fraser river, one of the most important rivers in canada. what is the most important species of fish in this river? why are the numbers of these fish declining?

In yusel komunnyakaa's camouflage the chimera what is a chimeraa animal coming to vietnamb a type of military outfitc mythological creatured nick name for military units