Chapter 21 Review
Fossils and the Rock
Record
The oldest rock layer in an undisturbed rock
sequence occurs
1. at the bottom of the
sequence
2. below the sedimentary
rock layer
3. below the unconformity
4. at the top of the
sequence
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
15
...
se
q
of
t
p
th
e
to
th
e
lo
w
at
be
16
he
on
fo
rm
ity
un
c
im
se
d
th
e
lo
w
be
14
en
ta
th
e.
..
of
tto
m
bo
th
e
at
1
r..
.
0% 0% 0% 0%
17
18
19
20
The amount of time it takes for one-half
of the original amount of an isotope to
decay is known as its
1.
2.
3.
4.
correlation
half-life
period
radioactivity
0%
c
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
n
tio
a
l
re
or
14
0%
h
ife
f-l
l
a
0%
rio
pe
0%
d
ra
15
16
17
18
di
iv
ct
a
o
ity
19
20
Evolution is the process by which
organisms
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
16
...
be
hi
nd
ev
i
er
ve
pr
es
e
m
e
le
av
co
be
15
de
nc
d
in
es
an
g
ch
o
tt
ap
ad
14
b.
..
ir .
.
th
e
d
gr
in
nd
ge
s
di
1
t..
.
.
0% 0% 0% 0%
ta
1. digest and grind their food
2. adapt to changes in their
environments
3. become preserved by
mineral replacement
4. leave behind evidence of
their existence
17
18
19
20
On the geologic time scale, the
smallest unit of time is called a(n)
0%
0%
h
n
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
17
oc
ep
pe
eo
er
0%
d
0%
rio
era
eon
period
epoch
a
1.
2.
3.
4.
18
19
20
When part of the rock record is
destroyed, the erosional gap that
forms is a(n)
0%
co
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
tio
n
su
un
1
0%
rp
os
i
y
ke
in
0%
pe
be
d
io
n
0%
nf
or
m
ity
inclusion
key bed
unconformity
superposition
cl
us
1.
2.
3.
4.
17
18
19
20
Which of the following is used to
determine the absolute age of a rock?
1.
2.
3.
4.
relative-age dating
correlation
permineralization
radiometric dating
0%
re
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
ti
la
-a
ve
ge
15
t
da
g
in
c
0%
la
re
or
n
tio
pe
16
0%
17
rm
e
in
ra
a
liz
n
tio
ra
18
di
ric
et
om
19
0%
da
g
tin
20
Index fossils are useful to geologists if the
fossils
1. have lived over a short
period of time
2. are not easily recognized
3. are not widely distributed
geographically
4. are scarce
h
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
0% 0% 0% 0%
e
av
ed
liv
e
ov
ra
a
15
re
o
sh
..
a
te
o
n
16
s
ily
re
ar
e
..
g.
co
tw
no
17
e
id
ly
d
18
.
ib
tr
is
..
ar
19
e
s
e
rc
a
c
20
What are fossil insects preserved in
hardened tree sap called?
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
ga
14
15
16
0%
be
r
s
0%
am
pr
ol
ite
fo
s
e
tr
ac
1
0%
st
ro
lit
hs
0%
co
trace fossils
gastroliths
coprolites
amber
si
ls
1.
2.
3.
4.
17
18
19
20
Molds, casts, coprolites, and petrified
wood are all example of
1. fossils
2. radioactive
isotopes
3. unconformities
4. disconformities
0%
f
si
os
ra
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
di
15
ls
c
oa
e
tiv
i
0%
e
op
t
so
16
s
un
c
0%
e
iti
m
r
fo
on
17
s
s
di
18
co
0%
iti
m
r
o
nf
19
es
20
The Phanerozoic Eon includes the
Paleozoic, Mesozoic, and
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
17
Er
as
ic
oz
o
en
C
Te
16
0%
ch
s
ry
Pe
r
si
c
ra
s
Ju
15
0%
Ep
o
ds
Pe
r io
oz
o
en
C
1
0%
io
ds
0%
rt
ia
Cenozoic Periods
Jurassic Periods
Tertiary Epochs
Cenozoic Eras
ic
1.
2.
3.
4.
18
19
20
The Archean and Proterozoic are
examples of
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
as
0%
er
hs
oc
pe
1
0%
ds
0%
rio
ns
0%
ep
eons
periods
epochs
eras
eo
1.
2.
3.
4.
17
18
19
20
Which of the following is marked by the
appearance of organisms with hard parts?
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
...
of
th
e
oz
o
eg
i
nn
i
ng
of
th
e
Me
s
Pr
ec
nd
eb
ee
th
th
th
ee
eb
nd
eg
i
nn
i
of
th
e
ng
of
th
e
a.
..
...
ic
0% 0% 0% 0%
th
1. the beginning of the
Cenozoic
2. the end of the
Precambrian
3. the end of the Mesozoic
4. the beginning of the
Cretaceous
17
18
19
20
Which of the following lists the units of
geologic time in order from shortest to
longest?
era, eon, period, epoch
epoch, eon, period, era
eon, era, period, epoch
epoch, period, era, eon
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
15
n
er
a,
er
io
d,
oc
h,
p
er
a,
ep
n,
eo
16
eo
ch
d,
e
pe
rio
,p
er
io
on
h,
e
oc
ep
14
po
d,
e
po
,p
er
io
on
a,
e
er
1
ra
ch
0% 0% 0% 0%
d,
e
1.
2.
3.
4.
17
18
19
20
An example of a fossil with original
preservation includes a(n)
1. insect imbedded in
amber
2. coprolite
3. dinosaur footprint
4. mold of a fish skeleton
0% 0% 0% 0%
in
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
ct
se
im
d
be
d
de
in
...
co
ite
ol
r
p
d
a
os
in
ur
in
pr
t
o
fo
m
15
16
17
d
ol
18
o
t
fa
fis
h
e
el
sk
19
n
to
20
An example of a fossil with altered
hard parts includes
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
d
wo
o
d
n.
..
tr i
fie
pe
ca
ti
a
sa
be
r- t
o
ot
he
d
ga
st
...
a
hu
m
an
a
1
ro
lit
h
0% 0% 0% 0%
m
um
m
ifi
ed
1. a mummified human
body
2. a gastrolith
3. a saber-toothed cat in tar
4. petrified wood
16
17
18
19
20
An example of a trace fossil includes a
ud
si
on
cr
ac
tra
il
or
m
0%
ra
in
d
ro
p
im
pr
es
st
0%
k
0%
w
of
a
cl
am
0%
m
cast of a clam
worm trail
mud crack
raindrop
impression
ca
1.
2.
3.
4.
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
17
18
19
20
Which correctly orders units of geologic time,
from most general to most specific?
1.
2.
3.
4.
eon, era, period, epoch
era, epoch, eon, period
period, era, eon, epoch
epoch, eon, period, era
0% 0% 0% 0%
eo
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
n
14
ra
,e
io
er
p
,
d,
er
15
o
ep
a,
ch
o
ep
o
,e
h
c
n,
rio
pe
pe
16
ri
d
,e
od
17
ra
o
,e
n,
ep
o
ep
ch
e
h,
oc
18
o
ri
pe
,
n
19
,e
od
ra
20
What is the correct
label for “C” on the
diagram?
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
0%
ce
le
o
Pa
rm
17
ne
ia
n
0%
ic
zo
le
o
Pa
le
o
Pa
1
0%
ne
0%
Pe
Paleogene
Paleozoic
Permian
Paleocene
ge
1.
2.
3.
4.
18
19
20
The shaded area of which graph represents
the percentage of geologic time that is part of
the Precambrian?
1.
2.
3.
4.
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
A
B
C
D
12
13
14
15
0%
0%
A
B
16
17
0%
0%
C
18
D
19
20
The principle of
superposition can be used to
determine
1. the actual age of these rock layers
2. the relative densities of these rock
layers
3. the actual temperatures of these
rock layers
4. the relative age of these rock layers
th
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
0% 0% 0% 0%
e
a
u
ct
al
ag
e
o
f
th
17
th
e
es
...
t
la
re
e
iv
d
en
th
18
e
ti
si
e
a
s
u
ct
..
al
t
p
em
th
19
u
at
er
e
...
t
la
re
e
iv
ag
e
o
20
f
th
.
e.
What classification of unconformity
occurs when sedimentary rock overlies
igneous rock?
un
c
nf
or
m
ity
0%
an
gu
la
r
co
ity
on
fo
rm
no
di
0%
rm
ity
0%
nc
sc
on
fo
rm
ity
0%
on
fo
1. disconformity
2. nonconformity
3. angular
unconformity
4. conformity
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
17
18
19
20
What characteristic of radioactive decay
makes it useful for determining the absolute
age of samples?
1. occurs at a constant rate
2. changes based on
temperature
3. speeds up under high
pressure
4. slows down in very dense
samples
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
ry
.
ve
in
ow
n
ow
sd
un
de
17
sl
up
ds
ee
sp
16
..
h.
..
rh
ig
t..
.
on
ed
ge
s
an
ch
oc
cu
rs
a
ta
ba
s
co
ns
ta
nt
.
..
0% 0% 0% 0%
18
19
20
Using the graph,
determine the halflife of thorium-232.
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
ar
s
ye
bi
ll
io
n
ye
io
n
bi
ll
io
n
bi
ll
14
16
0%
ar
s
0%
35
2
ye
ar
s
ye
n
7
1
0%
ar
s
0%
28
7 billion years
14 billion years
28 billion years
35 billion years
bi
lli
o
1.
2.
3.
4.
17
18
19
20
Radiocarbon dating can be used to
determine the age of what type of
materials?
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
15
flo
w
s
0%
va
or
ga
n
or
ga
in
g
liv
14
ni
c
is
m
k
ro
c
us
ne
o
ig
13
0%
la
0%
s
0%
m
at
er
ia
ls
1. igneous rock
2. living organisms
3. organic
materials
4. lava flows
16
17
18
19
20
The shaded area of which of these graphs
best represents the percentage of marine
organisms that became extinct at the end of
the Paleozoic?
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
B
0%
17
18
0%
0%
19
D
0%
C
A
B
C
D
A
1.
2.
3.
4.
20
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
17
18
en
re
s
en
ms
p
re
s
nis
Or
ga
ms
p
nis
Or
ga
19
t ..
.
td
...
t ..
.
en
re
s
ms
p
nis
Or
ga
Or
ga
nis
ms
p
re
s
en
t ..
.
Why are fossils of organism’s from the Phanerozoic eon
much more likely to be found than fossils of organisms
from any other eon?
1. Organisms present during the
Phanerozoic eon had only soft body parts.
2. Organisms present during the
Phanerozoic eon were all microscopic.
3. Organisms present during the
Phanerozoic eon had hard body parts.
0% 0% 0% 0%
4. Organisms present during the
Phanerozoic eon are the most ancient life
forms.
20
Present time is part of the
Mesozoic era.
1. True
2. False
0%
0%
ue
Tr
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
Fa
15
16
17
e
ls
18
19
20
Eons are longer units of time
than Eras.
1. True
2. False
0%
0%
ue
Tr
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
Fa
15
16
17
e
ls
18
19
20
The Precambrian consists of
the three earliest eons of
geologic time.
1. True
2. False
0%
0%
ue
Tr
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
Fa
16
17
e
ls
18
19
20
The star on the time line indicates
the beginning of the Precambrian.
1. True
2. False
0%
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
17
Fa
ls
e
Tr
ue
0%
18
19
20
Mammals and dinosaurs both
emerged during the Paleozoic
Era.
1. True
2. False
0%
0%
ue
Tr
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
16
Fa
17
18
e
ls
19
20
According to the principle of
superposition, the youngest rock
layers are closest to the surface.
1. True
2. False
0%
0%
ue
Tr
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
Fa
16
17
e
ls
18
19
20
Intrusions are younger than the
rocks they cut across.
1. True
2. False
0%
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
Fa
ls
e
Tr
ue
0%
15
16
17
18
19
20
An unconformity between two
sedimentary layers is classified
as a disconformity.
1. True
2. False
0%
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
Fa
ls
e
Tr
ue
0%
15
16
17
18
19
20
A geologist who needed to correlate
two rock formations in different
areas could use a key bed for this
work.
1. True
2. False
0%
0%
ue
Tr
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
Fa
16
17
18
e
ls
19
20
After one half life, the ratio of
parent atoms to daughter
atoms in a sample is 1:2.
1. True
2. False
0%
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
Fa
ls
e
Tr
ue
0%
15
16
17
18
19
20
The radioactive decay scale divides
the history of Earth into time units
that help geologists analyze the rock
record.
1. True
2. False
0%
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
15
Fa
ls
e
Tr
ue
0%
16
17
18
19
20
The remains of once living plants or
animals are called varves.
1. True
2. False
0%
0%
ue
Tr
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
14
Fa
15
16
17
e
ls
18
19
20
The principle of uniformitarianism
states that sedimentary rocks are
deposited in horizontal layers.
1. True
2. False
0%
0%
ue
Tr
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
Fa
14
15
e
ls
16
17
18
19
20
Dendrochronology is the science of
comparing annual growth rings in
trees to date changes in Earth's
environments and past events.
1. True
2. False
0%
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
13
Fa
ls
e
Tr
ue
0%
14
15
16
17
18
19
20
Key beds are time markers that
can be used to correlate rock
layers across large areas.
1. True
2. False
0%
1
2
3
4
5
6
7
8
9
10
21
22
23
24
25
26
27
28
29
30
11
12
Fa
ls
e
Tr
ue
0%
13
14
15
16
17
18
19
20