ACT SAMPLE SCIENCE TEST 13

ACT SAMPLE SCIENCE TEST 13
DIRECTIONS: This test consists of seven passages, each followed by several questions. Read each passage
and select the best answer for each question following the passage. Then, on your answer sheet, mark the
oval corresponding to the best answer. You may NOT use a calculator on this test.
Passage I
The Earth’s lithosphere, or crust, consists of tectonic plates that move. It is believed that at one
point in the past, all of the continents comprised one large landmass. Over time, the tectonic plates
shifted to form continents as we know them today. There is not a consensus in the scientific community
about why the tectonic plates move. Two scientists discuss their viewpoints.
Scientist 1
The tectonic plates are constantly moving, causing earthquakes and volcanic eruptions. A large
burst of energy along with this movement is what created the separate continents on the Earth. The
tectonic plates move as a result of convection currents within the fluid, lower layer of the Earth’s crust,
the asthenosphere. The plates rest on top of this hot, plastic substance of the mantle. The
asthenosphere moves in a circular motion, causing the plates to collide with each other on all sides. This
circular motion is evidenced by the multiple locations along each plate’s boundary where earthquakes
and volcanic eruptions occur.
Scientist 2
The tectonic plates only move with sudden bursts of lithospheric motion. Otherwise they are
stationary. The creation of the individual continents is the first evidence of this theory. There was
originally one large landmass. A sudden burst of energy caused the plates to move apart and form the
continents. Since that time there has not been much plate movement. The little movement that does
occur releases small bursts of energy in only one direction along a fault line. This is apparent when
looking at historical data and the fact that there are certain areas that are more affected by earthquakes
than others.
1) Which of the following phrases best describes the main point that the 2 scientists have in
common?
A) The movement of the tectonic plates created the continents.
B) The tectonic plates are constantly moving.
C) The tectonic plates are not linked to earthquake activity.
D) The movement of the tectonic plates is circular in nature.
2) You can infer from Scientist 1’s viewpoint that which of the following could cause an
earthquake?
F) A volcanic eruption
G) Tectonic plate collision
H) A small burst of energy
J) Stationary fault lines
3) Scientist 1’s viewpoint indicates that the material in the asthenosphere is:
A) liquid.
B) solid.
C) gaseous.
D) stationary.
4) Which of the following statements best describes how Scientist 2 would explain the occurrence
of many small earthquakes?
F) Constant tectonic plate movement creates large bursts of energy along plates’ boundaries.
G) Convection currents within the asthenosphere move the tectonic plates against each other.
H) Volcanic eruptions along the fault lines move in only one direction.
J) Limited tectonic plate movement releases small bursts of energy along the fault line.
5) According to the passage, the lower layer of the Earth’s crust is called the:
A) continental shift.
B) asthenosphere.
C) fault line.
D) lithosphere.
6) Which of the following statements would both scientists most likely use to explain the creation
of the continents? The tectonic plates experienced:
F) a large bursts of energy.
G) little movement.
H) many small energy bursts.
J) slow, gradual motion.
7) Scientist 1’s viewpoint would be weakened by which of the following statements about tectonic
plates, if true?
A) The tectonic plates rest on the rigid upper crust.
B) The tectonic plates experience constant motion.
C) The tectonic plates cause multiple earthquakes.
D) The tectonic plates experience large bursts of motion.
Passage II
Fire is the result of a chemical reaction between oxygen and a fuel, such as wood or gasoline,
that has been heated to its ignition temperature (the temperature that a fuel must reach before
combustion can begin). Once a fuel has been heated, it begins thermal degradation. Thermal
degradation is a process by which materials in the fuel are broken down into several by-products.
Wood, for example, breaks down into charred wood, ash, and a volatile gas (smoke). The actual burning
of wood will begin once the volatile gas has reached a high enough temperature. In this case, the
volatile gas must reach approximately 260°C before the wood will actually begin to burn.
A study was conducted to investigate the use of flame retardants in treating plywood samples to
reduce the risk of fire damage. Flame retardants reduce fire damage by interfering with the combustive
actions of fuels. In order to work, the flame retardant must suppress or slow down the combustion
process. Flame retardants can be used to suppress combustion at many different stages in the process.
This study focused on protective coatings that act as an insulator to protect against fire damage during
the beginning stages of combustion: thermal degradation and heat transfer.
Blocks of untreated pine plywood were tested at various temperatures in a controlled
environment. Three different types of fire retardant (inorganic salts) were used to treat several other
identical blocks of pine plywood that were tested at the same temperatures as the untreated plywood.
The percentage loss of mass was recorded for both the untreated and treated plywood samples after
being exposed to various temperatures, as shown in Figure 1 below.
8) At approximately 375°C, wood begins to break down into char and smoke. According to the
passage, this is called:
F) the combustion phase.
G) thermal degradation.
H) the ignition temperature.
J) the insulation point.
9) According to the passage, flame-retardant protective coating on wood is used to:
A) protect against the breakdown of the materials in the wood.
B) transform the volatile gases released into noncombustible material.
C) protect against the heat transferred during the final stages of combustion.
D) destroy any ash that was produced during combustion.
10) According to Figure 1, the untreated wood loses mass most quickly:
F) between 200° and 260°C.
G) between 260° and 400°C.
H) between 400° and 600°C.
J) between 600° and 700°C.
11) Which of the following is true of the plywood treated with Fire retardant 3, as compared to the
other samples of plywood used in the study?
A) Fire retardant 3 suppresses combustion more effectively than either Fire retardant 1 or Fire
retardant 2.
B) Fire retardant 3 only protects from the loss of mass at lower temperatures.
C) Fire retardant 3 is the least effective at temperatures about 600°C.
D) Fire retardant 3 is more effective than untreated wood, but less effective than Fire retardant
12) According to the passage, at about which temperature do Fire retardant 1 and Fire retardant 2
experience the same percent of mass loss?
F) 250°C
G) 425°C
H) 550°C
J) 625°C
Passage III
All scientists agree that carbon dioxide (CO2) is used by trees during photosynthesis. Trees and
other plants that undergo photosynthesis are often called carbon sinks because they absorb large
amounts of atmosphere carbon dioxide. It seems logical that planting more trees and cutting down
fewer trees would be the best solution to removing excess carbon dioxide from the atmosphere. Excess
carbon dioxide in the atmosphere is blamed for the greenhouse effect that may be leading to global
climate change.
Two scientists present their views on planting and preserving trees as a solution to eliminating
excess carbon dioxide in the atmosphere.
Scientist 1
Planting new trees and preserving existing trees is not a good long-term solution to eliminate
excess carbon dioxide in the atmosphere. As the world’s population increases, forests will need to be
converted into farms on which to grow food and raise livestock. In addition, planting more trees or
preserving trees may give people the impression that no other measures are needed to reduce carbon
dioxide emissions. Car pooling, conservation of electricity, and creation of cars that do not emit carbon
dioxide are necessary for long-term reduction of carbon dioxide in the atmosphere. Furthermore, dead
and decomposing trees emit carbon dioxide. Forest fires and droughts are just two forces that kill off
large numbers of trees and cause a rapid release of carbon dioxide into the atmosphere. In addition,
planting trees also accelerates climate change in snow-covered areas by reducing the amount of sunlight
energy that is directed back into space.
Scientist 2
Planting and preserving trees is a great long-term solution for reducing the levels of carbon
dioxide in the atmosphere. Planting and preserving trees can help reduce the destruction of the world’s
forests and protect biodiversity. Trees and forests are the largest carbon sinks on earth. In fact, 458
tons of carbon dioxide are absorbed and stored in one hectare of mature forests. Although some
carbon dioxide is released when the leaves decompose, planting or preserving trees is still and effective
means by which to greatly reduce the carbon dioxide levels in the atmosphere.
13) If Scientist 1 is correct, which of the following generalizations about carbon dioxide levels is
most accurate?
A) Planting trees is the only known way to decrease the levels of carbon dioxide in the
atmosphere.
B) Young forests do not store as much carbon dioxide as older forests.
C) It will not be possible to both reduce carbon dioxide levels and feed the growing population.
D) It will take more than 1 measure to effectively reduce carbon dioxide levels in the
atmosphere in the long run.
14) There have been periods of increased carbon dioxide levels in the atmosphere during hot, dry
summers. Scientist 1 would probably explain this by saying that:
F) hot and dry summers often lead to droughts and forest fires that kill large numbers of trees.
These dying trees release stored carbon dioxide into the air.
G) hot and dry summers most likely accelerate climate change because leaves grow smaller
and create less shade. This leads to the ground absorbing more sunlight than usual.
H) trees planted during hot and dry summers are less likely to flourish. They will grow to be
smaller than normal and absorb less carbon dioxide.
J) cool and wet weather allows trees to absorb more carbon dioxide because there is more
carbon dioxide present in the atmosphere.
15) In 2004, people reported that they believed the number one way to reduce CO2 levels in the
atmosphere was to plant or preserve trees. According to Scientist 2, what other benefits could
new and preserved forest areas provide?
A) Increased economic stability for people who harvest trees for furniture and lumber
B) Increased climate change as the trees absorb carbon dioxide from the atmosphere
C) Reduction in the destruction of forest areas and protection of biodiversity
D) Increased interest in decreasing the levels of carbon dioxide in the atmosphere
16) Which of the following is NOT mentioned by Scientist 1 as a solution to reducing CO2 in the
atmosphere?
F) Car pooling
G) Conservation of electricity
H) Solar power
J) Low-emission vehicles
17) According the information presented in the passage, Scientists 1 and 2 disagree about:
A) whether car pooling can reduce carbon dioxide levels in the atmosphere more than
conservation of electricity will.
B) whether planting and preserving trees is a good long-term solution to reducing the levels of
carbon dioxide in the atmosphere.
C) whether decomposing trees and leaves release carbon dioxide.
D) whether excess carbon dioxide can lead to global climate change.
18) An increase in newly planted trees in snow-covered areas has not accelerated climate change.
How might Scientist 1 account for this?
F) The newly planted trees have not yet grown large enough to reduce the amount of sunlight
energy directed back into space.
G) The newly planted trees are not absorbing as much carbon dioxide as mature trees.
H) The newly planted trees are not compensating for other practices that are increasing the
carbon dioxide levels in the atmosphere.
J) There has been an overall reduction in carbon dioxide levels from droughts and forest fires.
19) Which of the following findings, if true, would weaken the arguments of Scientist 2?
A) Cities that encourage car pooling have lower levels of carbon dioxide in their atmospheres
than cities that do not encourage carpooling.
B) Decomposing leaves reemit 99% of the carbon dioxide that a tree absorbs.
C) Sales of cars that emit less carbon dioxide are rapidly growing in areas with snow-covered
terrain.
D) Planting trees in areas that receive little or no snow has not been found to accelerate
climate change.
Passage IV
The color of a leaf results from an interaction of different pigments (colored substances)
produced by the plant. The main pigment classes responsible for leaf color are porphyrins, carotenoids,
and flavonoids. The leaf color that we see depends on the amount and types of pigments present.
The primary porphyrin in leaves is a green pigment called chlorophyll. Chorophyll is produced in
response to sunlight. As the seasons change and the amount of sunlight decreases, less chlorophyll is
produced by the leaves, and leaves appear less green. Chlorophyll is broken down at a constant rate, so
green leaf color will gradually fade as chlorophyll production slows or stops.
Light is not needed in order for a plant to produce carotenoids; therefore, these pigments are
always present in a living plant. One of the flavonoids, anthocyanin, provides a natural sunscreen for
plants.
Chlorophyll masks the other pigment colors, so when it is present, leaves will appear green.
Anthocyanins, in turn, mask carotenoids. As summer turns to autumn, decreasing light levels cause
chlorophyll production to slow. At the same time, anthocyanin production in leaves increases. Leaves
containing primarily anthocyanins will appear red. Leaves with large amounts of both anthocyanins and
carotenoids will appear orange. Leaves with carotenoids but little or no anthocyanins will appear
yellow.
Table 1 shows the three main pigment classes, the compounds that make up the pigments, and
the leaf colors that they produce.
Table 1
Compound
type
Chlorophyll
Resulting
colors
Green
Carotenoid
Carotene and
lycopene
Yellow,
orange,red
Flavonoid
Xanthopyll
Flavone
Flavonol
Anthocyanin
Yellow
Yellow
Yellow
Red, blue, purple
Pigment
class
Poryphyrin
20) According the the passage, chlorophyll production:
F) increases the amount of carotenoids.
G) is dependent upon sunlight.
H) slows down in the summer.
J) decreases the amount of pigment.
21) Based on Table 1, the presence of which of the following compounds produces yellow leaves?
A) Lycopene only
B) Chlorophyll only
C) Lycopene and anthocyanin
D) Lycopene, flavone, and carotene
22) Is the statement “decreased light levels have little to no effect on color changes in leaves”
supported by information presented in the passage, and why?
F) Yes, because light is not needed for a plant to produce flavonol, which causes leaves to
change from green to yellow.
G) Yes, because chlorophyll breaks down at a constant rate.
H) No, because chlorophyll is produced in response to sunlight, and decreasing light levels slow
chlorophyll production.
J) No, because anthocyanin provides a natural sunscreen for plants.
23) According to the passage, leaves with more anthocyanins than carotenoids will:
A) retain their green color.
B) appear red.
C) appear yellow.
D) not produce chlorophyll.
24) According to the passage, of the main pigment classes, which has the most color variety?
F) Porphyrin
G) Chlorophyll
H) Flavonoid
J) Carotenoid
Passage V
The meerkat is a member of the mongoose family that lives on the African grasslands. Unlike
other mongooses, meerkats live in large social communities of up to 30 members. These groups are
called “mobs” or “gangs.” Often at sunrise, all of the members of a gang will gather together, stand up,
and turn their bellies to the sun, soaking up the sunligt.
In addition to being social, meerkats are very territorial, and they will fiercely defend their
homes against other meerkat gangs, as well as against all other intruders. Meerkat “sentries” can often
been seen scanning the horizon for predators, standing up on their hind legs and using their tails for
balance. When a predator or other intruder appears, a sentry will make an alarm call, alerting the
others members of its gang to possible danger. Known meerkat predators include eagles and jackals.
Meerkats feed on small mammals, birds, and reptiles, as well as eggs and the roots of some
plants. Scorpions are considered a special treat for meerkats; the scorpion’s stinger is quickly bitten off
before the rest of the animal is consumed. It is thought that meerkats use specialized vocalizations to
alert the gang of the presence of food.
Zoologists have been studying meerkat alarm calls to determine whether they have special
meanings. A gang of meerkats was observed for several days. The observer noted the type of call that
was made, and the possible reason for the alarm call (approaching predator, etc.). The aggregate results
of these observations are presented in Table 1 below.
Table 1
Meerkat alarm call
Time of day
Possible alarm call cue
One quick “chirp”
Sunset or sunrise only
None observed
Series of repeating quick “chirps”
Throughout the day
Individual meerkat from another
gang; small group of meerkats
from another gang
Constant loud “chattering”
Throughout the day
Jackal, eagle, large snake
Three quick “chirps” followed by
a short pause and three more
“chirps”
Throughout the day
Meerkat from the sentry’s gang
25) Based on Table 1, when a meerkat sentry begins to chatter constantly, it is most likely signaling:
A) the end of the day.
B) the approach of a meerkat from another gang.
C) the approach of a predator.
D) the presence of a food source.
26) Meerkats have been called the “Solar Panel of the Animal World.” The most likely reason for this
is:
F) the meerkats’ natural habitat on the African grasslands.
G) the meerkats’ habit of soaking up morning sun.
H) the meerkats’ ability to make speacialized alarm calls.
J) the meerkats’ ability to stand up on their hind legs.
27) According to the passage, as compared to other mongooses, meerkats:
A) eat small animals and birds.
B) live in Africa.
C) do not live in large social groups.
D) live in large social groups.
28) Which of the following statements is most consistent with the results shown in Table 1?
F) Meerkats vocalize for reasons other than to warn each other of possible danger.
G) Meerkats will only vocalize when predators are close by.
H) Meerkats have specialized alarm calls for each type of predator.
J) Meerkats will not vocalize if a member of a rival gang approaches.
29) Which of the following assumptions about meerkat alarm calls was made before the
observations were noted?
A) None of the meerkats in rival gangs be able to hear the alarm calls made by the sentries.
B) All of the meerkats in a certain gang will recognize and understand the different alarm calls
made by the sentries.
C) Only the alarm calls made after sunrise would be considered important.
D) Meerkat predators may be able to mimic the alarm calls made by the sentries.
30) Which of the following, if it had occurred, would NOT support the theory that meerkat alarm
calls have special meanings?
F) The sentries repeated the same alarm call to indicate the presence of both predators and
members of rival gangs.
G) The sentries varied the alarm calls depending on what type of predator was approaching.
H) Different alarm calls were made depending on the direction from which the predator was
approaching.
J) The sentries altered the alarm call to indicate the proximity of the approaching rival gang.
Passage VI
The oceans of the world contain millions of creatures and animals, and more are being
discovered each day. Every animal found in the ocean has special characteristics that define its living
conditions, or, more specifically, the different zones of the ocean in which each animal will best survive.
Figure 1 shows the different zones of the ocean, beginning at the surface and continuing to the sea
floor, which can extend as far as 11,000 meters (m) in some locations.
In the midwater zone (200 m-2,000 m) of the ocean, many fish must adapt to the scarce food
supply. The debris that falls from more shallow waters and the other animals that live there make up
the available food supply. Most of these animals have relatively low levels of protein in their muscles,
making them very weak. Most likely, these characteristics are adaptations to the low-energy
environment. To compensate, the animals have unique mechanisms to ensure survival even though
feedings are infrequent: mouths that expand two times the size of their bodies, large stomachs, and
large teeth to maximize the size of prey that they can consume, as well as large eyes and photophores,
(organs that produce light) which make is possible to survive in an environment with little to no light.
Table 1 shows several animals that live at various depths of the ocean. Although most animals generally
stay within a certain range of depths, some are found in much deeper zones.
Animal
Snipe Eel
Table 1
Found at depths (m)
40-550
Max depth (m)
2,000
Crested Bigscale
600-2,100
3,200
Eelpout
2,500-5,000
5,000
Cuskeel
1,975-5,200
5,200
Stout Blacksmelt
225-1,400
6,700
Some midwater species are vertical migrators that travel up to 1,500 feet each day. At night,
they travel closer to the surface (at the uppermost part of their range of depth) to feed in areas where
more food is available, and then travel back down during the day (to the lowermost part of their range
of depth). These creatures travel at night to reduce the chances of being seen and preyed upon.
31) Based on information in the passage, which of the following is the most likely reason for the
expandable mouth of a midwater species? The expandable mouth is used:
A) to catch and consume available prey that may be larger in size.
B) to absorb more carbon dioxide from the deep-sea waters.
C) to make use of the sensory pores inside the mouth.
D) to communicate with other animals.
32) According to the passage, the midwater zone includes which of the following ocean zones?
F) Epipelagic and mesopelagic
G) Mesopelagic and bathypelagic
H) Bathypelagic and abyssopelagic
J) Abyssopelagic and hadopelagic
33) According to the passage, the snipe eel may be found in which ocean zones?
A) Epipelagic only
B) Epipelagic and mesopelagic
C) Mesopelagic only
D) Epipelagic, mesopelagic, and bathypelagic
34) According to the passage, if eelpouts are vertical migrators, to which depth might they travel at
night?
F) 225 m below the surface.
G) 1,400 m below the surface.
H) 2,500 m below the surface.
J) 5,000 m below the surface.
35) The worldwide average temperature of the ocean from the surface down to 400 m below the
surface is 22°C. From 400 to 800 m, the temperature drops drastically, and the temperatures
range from 0°C to 4°C from this point down to the sea floor. According to Table 1 and the
information given, which of the following animals would best survive at any temperature from
the surface to the deep sea?
A) Cuskeel
B) Crested bigscale
C) Stout blacksmelt
D) Eelpout
Passage VII
When 2 female snakes of a certain species encounter each other, there is often a threat display.
The dominant snake usually forces the submissive snake to coil. A biologist conducted 2 experiments to
determine the rank in aggression of female snakes. In the experiments described below, 5 adult female
snakes were placed together in a cage and their interactions were observed and recorded.
Experiment 1
To determine what factors might affect aggressiveness, the biologists recorded the sequence in
which the snakes were placed in the cage, their length, their ages, and the number of hisses each snake
made during the experiment. In addition, the snakes were ranked according to their aggressiveness
toward one another, from most aggressive (1) to least aggressive (5). The results are shown in Table 1.
Snake
Sequence
A
B
C
D
E
1st
2nd
3rd
4th
5th
Table 1
Length (cm)
Age in years
50
30
40
60
20
3
5
2
4
1
Number of
Hisses
26
10
31
20
17
Aggression
(rank)
2
5
1
3
4
Experiment 2
The snakes were placed back into the cage in the same sequence as in Experiment 1. The results
of all aggressive encounters between pairs of snakes were recorded. A snake was declared a “winner” if
it forced the other snake, the “loser,” to coil. Table 2 shows the results of the interactions between the
snakes. There were no draws, or ties, observed.
Table 2
Winning Snake
A
B
C
D
E
A
0
15
35
0
B
0
20
5
10
C
30
0
5
15
D
20
10
20
15
E
10
5
20
10
-
Table 3 summarizes the results of all the encounters for each snake.
Table 3
Snake
A
B
C
D
E
Wins
60
15
75
55
40
Losses
50
35
50
65
45
Encounters
110
50
125
120
85
36) Which of the following generalizations about the relationship between snake length and rank is
consistent with the experimental results.
F) The longest snake will be the most dominant.
G) The longest snake will be the most submissive.
H) Length has no effect on rank.
J) The shortest snake will be the most dominant.
37) It would suggested that the more dominant a female snake was, the safer her eggs were.
Accordingly, one would predict, based on win-loss records, that the snake with the safest eggs
would be:
A) Snake B
B) Snake D
C) Snake C
D) Snake A
38) A sixth snake whose length was 55 centimeters and whose age was 3 years, was added to the
experimental cage. It was observed that the snake hissed a total of 21 times during the
experiment. Based on the results of Experiment 1, what would be the rank of the sixth snake in
terms of its aggressiveness?
F) 1
G) 3
H) 4
J) 5
39) According to the results of Experiments 1 and 2, which of the following factors is (are) related to
the number of hisses the snake will make?
I. Age
II. Length
III. Aggressiveness
A) I and II only
B) I and III only
C) II only
D) III only
40) One can conclude from the results of Experiment 2 that snake C and snake A had a total of how
many encounters with each other?
F) 15
G) 35
H) 45
J) 75
Sample Science Test 13 Answers
1)
2)
3)
4)
5)
6)
7)
A
G
A
J
B
F
A
8)
9)
10)
11)
12)
13)
14)
G
A
G
A
J
D
F
15)
16)
17)
18)
19)
20)
21)
C
H
B
F
B
G
D
22)
23)
24)
25)
26)
27)
28)
H
B
H
C
G
D
F
29)
30)
31)
32)
33)
34)
35)
B
F
A
G
D
H
C
36)
37)
38)
39)
40)
H
C
G
D
H