Name Class Date
Chapter 14The Ocean FloorChapter Test
Multiple Choice
Write the letter that best answers the question or completes the statement
on the line provided.
1.What percentage of Earth’s surface is covered
by water?
a.45 percent
b.51 percent
c.71 percent
d.85 percent
2.Which of the world’s oceans is the largest
and deepest?
a.Arctic Ocean
b.Atlantic Ocean
c.Indian Ocean
d.Pacific Ocean
3.Which of these features is NOT found on the
ocean floor?
a.mountain
b.volcano
c.river
d.plain
4.What does sonar equipment measure?
a.the density of the ocean’s water
b.the depth of the ocean floor
c.the sound produced by bottom-dwelling
ocean creatures
d.the shape of the ocean surface
5.Scientists use satellites to measure the
a.ocean floor depth.
b.size of underwater features.
c.sea-surface height.
d.ocean’s salinity.
6.Which of the following areas is NOT one of the
three main regions of the ocean floor?
a.ocean floor basin
b.continental margins
c.continental rock
d.mid-ocean ridge
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7.The continental margins of the Pacific Ocean are
a.wider than those of the Atlantic and have more
earthquake activity.
b.narrower than those of the Atlantic and are not covered
with thick layers of sediment.
c.wider than those of the Atlantic and have no volcanic or
earthquake activity.
d.narrower than those of the Atlantic and are covered with
thick layers of sediment.
8.Trenches form at sites where
a.one plate descends beneath another.
b.erosion cuts into the continental shelf.
c.two plates diverge under the sea.
d.the tops of undersea volcanoes collapse.
9.Abyssal plains are very flat features that form when
a.volcanoes spread lava on the ocean bottom.
b.turbidity currents deposit sediments on the ocean floor.
c.ocean waters flood plains on land.
d.plates diverge on the ocean floor, causing seafloor
spreading.
10.Which of the following forms at mid-ocean ridges?
a.island arcs
b.deep-sea trenches
c.guyots
d.new ocean floor
11.The three types of ocean floor sediments are classified
according to their
a.color.
b.origin.
c.particle size.
d.hardness.
12.Terrigenous sediment consists primarily of mineral grains
eroded from
a.mid-ocean ridges.
b.marine animal shells.
c.continental rocks.
d.undersea minerals.
13.From which type of material does biogenous sediment form?
a.once-living organisms
b.manganese nodules
c.rocks on land
d.cooled magma
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14.Hydrogenous sediment is made up of
a.cinders and rock from undersea volcanoes.
b.parts of once-living organisms.
c.eroded continental rock.
d.minerals that crystallize directly from ocean waters.
15.What are the two major energy sources obtained from the
ocean floor?
a.oil and manganese
b.calcium carbonate and halite
c.natural gas and coal
d.oil and natural gas
16.Which of the following areas does NOT contain major
deposits of energy resources?
a.Persian Gulf
b.Hudson Bay
c.Gulf of Mexico
d.North Sea
17.Most oceanic gas hydrates form when
a.bacteria break down organic matter in seafloor sediments.
b.plant matter breaks down to form peat.
c.petroleum deposits seep into ocean floor sediment.
d.chemicals in ocean water precipitate out of solution.
18.Gas hydrates are compact chemical structures made of
natural gas and
a.halite.
b.water.
c.manganese.
d.petroleum.
19.Which offshore resources are second only to petroleum in
economic value?
a.salts and gypsum
b.manganese nodules and halite
c.calcium carbonate and copper
d.sand and gravel
20.Manganese nodules are
a.manganese salts that concentrate when seawater
evaporates.
b.lumps of manganese and other metals found on the
ocean floor.
c.deposits of manganese and iron deep under the
ocean floor.
d.chunks of pure manganese found in deep-sea trenches.
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Completion
Complete each statement on the line provided.
1.Earth is often called the “blue planet” because
covers much of its surface.
2.The world ocean can be divided into
main basins.
3.The measurement of ocean depth and the mapping of the
topography of the ocean floor is called .
4.The ship HMS made the first study of the
global ocean in the 1870s.
5.Scientists can use sonar to get a profile of a
strip of ocean floor instead of simple sonar, which maps only a
point on the ocean floor every few seconds.
6.A small underwater craft used for deep-sea research is a(n)
.
7.The is the gently sloping submerged surface
extending from the shoreline.
Use Figure 1 to answer the
following three questions.
8.Using Models This diagram
shows a wide continental margin
like those along the coast of the
Ocean.
9.The features at A are submarine
.
10.The continental margin slopes down to the
plain on the ocean floor.
11.Occasional movements of dense, sediment-rich water down the
continental slope are currents.
12.The steep continental slope merges into a more gradual incline
known as the continental .
13.Seamounts are submerged on the ocean floor.
14.The deepest known place on Earth is the in
the Pacific Ocean’s Mariana Trench.
15.The mid-ocean ridge is an interconnected system of underwater
.
16.Most of the ocean floor is covered by deposits of
.
17.The two types of biogenous sediments are
ooze and ooze.
18.When metals precipitate around grains of sand, a
nodule can form.
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19.Calcium carbonate is a type of hydrogenous sediment that can be
buried and harden into .
20.Environmental concerns about offshore oil drilling include oil
, which can pollute water.
21.Gas hydrates burn because they release and
other flammable gases as they evaporate.
22.Some offshore sand and gravel deposits contain valuable materials
such as precious metals and .
Short Answer
In complete sentences, write the answers to the questions on the lines provided.
1.List the world’s main oceans, from the largest to the smallest.
2.Comparing and Contrasting Describe the topography of the
ocean floor, comparing it to topography on land.
3.Describe the way sonar works.
4.Why are submersibles more useful than sonar and satellites for
studying undersea life?
5.Is there more volcanic and earthquake activity at the continental
margins of the Pacific Ocean or the Atlantic Ocean? Explain
your answer.
6.Drawing Conclusions Nations often compete to control the
continental shelves along their coasts. What economic advantage
might be gained by controlling continental shelves?
7.What is the relationship between a submarine canyon and the
continental slope?
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8.How does a volcanic island become a guyot?
9.What type of plate boundary is found at a mid-ocean ridge, and
what happens at the edge of these plates?
10.What is siliceous ooze composed of?
11.Applying Concepts If a scientist finds biogenous sediment on the
deepest part of the ocean floor, which type of biogenous sediment
is it more likely to be? Explain your answer.
12.Evaluating Describe a major drawback to the use of gas hydrates
as a major energy source.
Essay
In complete sentences, write the answer to the question on the lines provided.
1.Earth as a System Describe the material exchange that takes place
among the ocean floor, the hydrosphere, and the ocean biosphere.
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