Unit 7 Test Review
Ms Grant
Trace fossils are much more common than body
fossils. Which of the following best explains why trace
fossils are more common?
A. Trace fossils take less time to form.
B. Body fossils require soft sediment to form.
C. An organism is more likely to live on soft
sediment where trace fossils form.
D. A single animal can leave thousands of traces
in its lifetime but will leave only one body when
it dies.

AND THE ANSWER IS……………
D. A single animal can leave
thousands of traces in its lifetime
but will only leave one body when
it dies
What materials does radiometric dating use
to determine the age of objects?
A.
B.
C.
D.
fossils
isotopes
tree rings
rock layers

AND THE ANSWER IS……………
B. isotopes
An igneous intrusion cuts through three
layers of sedimentary rock. Which rock
is the youngest?
A.
B.
C.
D.
the
the
the
the
igneous intrusion
top layer of sedimentary rock
middle layer of sedimentary rock
bottom layer of sedimentary rock

AND THE ANSWER IS……………
A. the igneous intrusion
What is the law of superposition?
A. Igneous rock is older than nearby sedimentary rock, which is
older than nearby metamorphic rock.
B. A sedimentary rock layer in its original position is older than the
layers above it and younger than the layers below it.
C.Metamorphic rock is older than nearby sedimentary rock because
sedimentary rock is deposited before metamorphic rock forms.
D.The exact age of a sedimentary rock layer can be found using the
layers above and below it, even if the layers are not in their
original positions.

AND THE ANSWER IS……………
B. A sedimentary rock layer in its
original position is older than the
layers above it and younger than
the layers below it.
Earth’s surface features slowly change over
time. For example, sharp, jagged
mountain ranges become lower and more
rounded over time. What factor/s is
responsible for this change in their shape?
A. weathering and erosion
B. deposition
C. movement of continents
D. collisions between continental plates

AND THE ANSWER IS……………
A. weathering and erosion
Chase wants to determine a more accurate age
of a shell that is known to be between 10,000
and 30,000 years old. Which method would
be most useful for finding a more precise
age of the shell?
A. radiocarbon dating
B. uranium-lead dating
C. potassium-argon dating
D. relative dating

AND THE ANSWER IS……………
A. radiocarbon dating
Radiocarbon dating has a shorter useful time range
than potassium-argon dating. Which statement best
explains why?
A. Carbon-14 is a common component of living things.
B. Carbon-14 is not a common component of minerals.
C. Carbon-14 has a longer half-life than potassium-40.
D. Carbon-14 has a shorter half-life than potassium-40.

AND THE ANSWER IS……………
D. Carbon-14 has a shorter
half-life than potassium-40
Each radiometric dating method is useful
for a specific time range. Which method has
the most useful time range of 100,000 to a
few billion years old?
A. relative dating
B. radiocarbon dating
C. uranium-lead dating
D. potassium-argon dating

AND THE ANSWER IS……………
D. potassium-argon dating

A geologist is studying three layers of sedimentary rock in
an area. The layers have not shifted from their original
positions. The geologist records the relative ages of the
rocks. The bottom layer is listed as the oldest. The top
layer is listed as the youngest. What did the geologist use
to determine the relative ages of the rocks?
A.
B.
C.
D.
mineral content
radioactive decay
the law of superposition
the principle of unconformity

AND THE ANSWER IS……………
C. the law of superposition
Which of the following methods is most
likely to be used to determine the
absolute age of animal bones that are less
than 45,000 years old?
A.
radiocarbon dating
B.
potassium-argon dating
C.
uranium-lead dating
D. relative dating


AND THE ANSWER IS……………
A.
radiocarbon dating

Jun makes a poster to explain how the law of superposition
applies to rock layers. He explained the ages of the top
three layers. He still needs to explain the age of layer 1.
His diagram is shown below.
How should he explain the age of layer 1?
A.
It is the youngest layer because it is protected by the
other layers.
B.
It is the oldest layer because it was deposited before
the other layers.
C.
It is older than layer 2 because it is thicker and has
been worn away the least.
D.
It is three times younger than layer 4 because it is
three layers below layer 4.

AND THE ANSWER IS……………
B. It is the oldest layer
because it was deposited
before the other layers.

Layers of rock are not always found in uniform layers. They
may be cut by faults. Melted rock may be pushed into the
layers, where it becomes solid. The diagram shows rock
layers that are cut by a fault and two bodies of rock (rock 1
and rock 2).
What are the relative ages of the features in order of oldest to
youngest?
A.
fault, rock 1, rock 2, layer 1
B.
layer 1, rock 2, rock 1, fault
C.
rock 2, layer 1, rock 1, fault
D.
fault, rock 2, layer 1, rock 1

AND THE ANSWER IS……………
B.
layer 1, rock 2, rock 1, fault

The diagram below shows one kind of
radioactive decay that is used for dating.
Which statement best describes what information is needed to
determine the age of a rock sample using this type of dating method?
A.
the exact mass of uranium-238 in the sample
B.
the amount of lead-206 present in the sample
C.
the energy being released by the uranium-238
D.
the relative amounts of uranium-238 and lead-206

AND THE ANSWER IS……………
D. the relative amounts of
uranium-238 and lead-206

During most of Florida’s geologic history,
the state was covered by the ocean.
Today, the land surface of Florida is
covered mostly by sediment and
sedimentary rock. If you were to analyze
the composition of Florida’s sedimentary
rocks, which type of fossil would you
least likely find?
A.
B.
C.
D.
fossils
fossils
fossils
fossils
of
of
of
of
seashells
fish bones
palm fronds
marine organisms

AND THE ANSWER IS……………
C.
fossils of palm fronds

Scientists from three parts of Florida are
comparing the rock layers in their areas.
They want to arrange the layers according
to their relative ages. The diagram shows
the rock layers from each area.
Which area has the youngest top layer compared to the other areas?
A.
area 1
C. area 3
B.
area 2
D. The ages of the top layers are all the same.

AND THE ANSWER IS……………
A. area 1

Scientists have discovered dinosaur
fossils that have evidence of feathers.
Some scientists think the feathers might
have kept the dinosaurs warm. If so, in
what type of environment did these
dinosaurs probably live?
A.
B.
C.
D.
hot desert
tropical rain forest
region near the equator
area with cold seasonal temperatures

AND THE ANSWER IS……………
D. area with cold seasonal
temperatures
To determine when a volcano erupted,
Michael used a sample of a mineral that
formed when the lava cooled and became
solid rock. He measured the amount of
argon-40 in the sample to find how much
potassium-40 had decayed since the rock
formed. What else would Michael need to
know to find the age of the mineral in
years?
A.
the half-life of potassium-40
B.
the amount of energy released
C.
the mass of a potassium-40 atom
D. the time it takes argon-40 to decay


AND THE ANSWER IS……………
A.
the half-life of potassium-40
GOOD LUCK!!!