13. Two things determine the rate at which water moves through an aquifer. One is the hydraulic conductivity (permeability) of the material. The other is (a) The slope of the water table
(b) The distance that the water flows
(c) The volume of water
(d) The pore pressure of the aquifer

14. Soils scientists classify soils based on

(a) the relative content of sand, silt and clay
(b) the porosity and permeability of the material
(c) the relative thickness of the soil horizons
(d) the original material it was derived from

15. The processes which drive the movement of the lithospheric “plates” are part of a planetary-scale system which works to

(a) equalize the density differences between the core and the surface
(b) equalize the pressure differences between the core and the lithosphere
(c) equalize the temperature differences between the core and the universe
(d) equalize the kinetic differences between the mantle and the crust

16. On their floodplains, rivers have a meandering habit. Over time, those meanders get larger and larger. The process by which they grow is a reflection of how

(a) The rate of erosion decreases with the depth of the water
(b) Groundwater flow affects slope stability
(c) Changes in water speed affect erosion and deposition
(d) Rivers are constantly eroding away their banks

17. Moving water sorts sediments based on

(a) their mineral composition
(b) their size
(c) their density
(d) their hardness

18. Metallic mineral resources are usually mined in places

(a) Where they have been accumulated by rivers
(b) Where the land was formerly covered by oceans
(c) Where volcanic processes have concentrated them
(d) Where erosion has cut down to the upper mantle

19. As we have studied the areas around our local volcanoes, we have come to realize that

(a) most of the valleys are filled with thick volcanic mudflows
(b) glowing pyroclastic flows have extended far from these mountains
(c) extensive ash-fall deposits have completely filled the surrounding valleys
(c) our volcanoes are not particularly hazardous, except for Mt. St. Helens