21. describe each of the four mechanisms that cause air to rise.(4 points)

How can minerals crystallize from materials dissolved in water? check all that apply.

Technology has affected regional settlement patterns in what ways? choose all that apply. climatic improvement strategies have improved crop productivity. mechanized agricultural methods have improved agricultural productivity. participation in the global economy has increased urbanization. population shifts from urban to rural areas has increased as a result of petroleum production. settlement areas have increased as a result of improved water storage and delivery systems.

Iii-eneral sciencewhich of these is the best explanation of how a smooth round stone became smooth? a continuous freezing and thawingbvolcanic actioncit fell off the side of a cliffdit was in a stream for a long time.