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Earth’s Crust Quiz
1) Relative to oceanic crust, continental crust is
a) Thinner.
b) Denser.
c) More mafic.
d) Made of a wider assortment of rocks.
2) Earth’s crust is
a) Pretty similar all the way around.
b) Very different between continental and oceanic crust types.
c) Made primarily of granite.
d) All of the above
3) Oceanic crust is
a) Basalt lava on top of gabbro.
b) A granitic layer with sediments on top.
c) Almost all formed from basalt lava.
d) Almost all formed from granitic rock.
4) The sediments that top the oceanic crust are primarily
a) Sands blown from the land.
b) Fossils of fish and marine mammals.
c) Mud and tiny marine fossils.
d) There are no sediments on the oceanic crust.
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5) The oceanic crust is mostly made of magma that has the composition of this rock.
a) Quartz
b) Granite
c) Basalt
d) Obsidian
6) Because continental crust is thicker and less dense than oceanic crust, it sinks
into the mantle to form basins.
a) True
b) False
7) Earth has continents and oceans because
a) Continental crust sinks below oceanic crust.
b) Oceanic crust sinks below continental crust.
c) Oceanic crust rises above continental crust.
d) None of these.
8) Continental crust is made up of
a) Igneous rock
b) Metamorphic rock
c) Sedimentary rock
d) All of the above
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9) Ocean basins form because the upper mantle can flow and the dense oceanic
crust sinks into it.
a) True
b) False
10) Crust is thick relative to Earth’s radius.
a) True
b) False
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