Choose the best answer.

1		Minerals are ________________.
			A)	silicon compounds
			B)	common types of rock
			C)	homogeneous solids of which rocks are composed
			D)	always compounds
2		The most abundant mineral in the earth's crust is _________________.
			A)	quartz
			B)	mica
			C)	feldspar
			D)	calcite
3		Rocks that have been formed by cooling from a molten state are called _________________.
			A)	igneous rocks
			B)	sedimentary rocks
			C)	metamorphic rocks
			D)	precipitated rocks
4		Rocks that have been altered by heat and pressure beneath the earth's surface are called ________________.
			A)	igneous rocks
			B)	sedimentary rocks
			C)	metamorphic rocks
			D)	precipitated rocks
5		The majority of surface rocks are ________________.
			A)	sedimentary
			B)	metamorphic
			C)	igneous
			D)	found in the mantle as well
6		A general characteristic of rocks of volcanic origin is __________________.
			A)	the presence of shale
			B)	a light color
			C)	course-grained structure
			D)	fine-grained structure
7		Most earthquakes are caused be __________________.
			A)	volcanic eruptions
			B)	landslides
			C)	lightning
			D)	shifts of crustal rocks
8		Regions in which earthquakes are frequent are also regions in which _________________.
			A)	the geomagnetic field is strong
			B)	hurricanes are common
			C)	volcanoes occur
			D)	petroleum is found
9		The earth's crust _________________.
			A)	has very nearly the same thickness everywhere
			B)	varies irregularly in thickness
			C)	is always thinnest under the continents
			D)	is always thinnest under the oceans
10		The part of the earth with the greatest volume is the _______________.
			A)	inner core
			B)	outer core
			C)	mantle
			D)	crust
11		The rocks of the mantle are believed to consist largely of __________________.
			A)	feldspar
			B)	quartz
			C)	clay minerals
			D)	ferromagnesian minerals
12		The reasons why the earth's core is believed to be largely molten iron do not include the __________________.
			A)	magnetic properties of iron
			B)	electrical conductivity of iron
			C)	density of iron
			D)	relative abundance of iron in the universe
13		Most of the earth's interior is believed to __________________.
			A)	be left over from its formation
			B)	come from radioactive materials
			C)	be due to chemical reactions in the core
			D)	be provided by solar radiation absorbed by the crust
14		The earth's magnetic field ________________.
			A)	never changes
			B)	has reversed itself many times
			C)	is centered exactly at the earth's center
			D)	originates in a permanently magnetized iron core
15		The principal agent of erosion is _________________.
			A)	groundwater
			B)	running water
			C)	ice
			D)	wind
16		The approximate percentage of the earth's land area covered by ice today is __________________.
			A)	1 percent
			B)	2 percent
			C)	10 percent
			D)	30 percent
17		The largest amounts of sediment are deposited ________________.
			A)	by glaciers
			B)	on river beds
			C)	on the ocean floors
			D)	by chemical precipitation
18		Most caves are produced by the solvent action of groundwater on ___________________.
			A)	limestone
			B)	sandstone
			C)	granite
			D)	schist
19		The holes found in most volcanic rocks are due to _______________.
			A)	gases trapped in solidifying lava
			B)	erosion
			C)	marine organisms
			D)	rapid cooling
20		Active volcanoes are not found _________________.
			A)	in the West Indies
			B)	in the Mediterranean region
			C)	on the rim of the Pacific Ocean
			D)	in eastern Canada