X
Test Information
Guide:
College-Level
Examination
Program®
2012-13
Natural Sciences
© 2012 The College Board. All rights reserved. College Board, College-Level Examination
Program, CLEP, and the acorn logo are registered trademarks of the College Board.
CLEP TEST INFORMATION
GUIDE FOR NATURAL SCIENCES
and also — in forward-deployed areas — through
paper-based testing. Approximately one-third of all
CLEP candidates are military service members.
History of CLEP
2011-12 National CLEP Candidates by Age*
Since 1967, the College-Level Examination Program
(CLEP®) has provided over six million people with
the opportunity to reach their educational goals.
CLEP participants have received college credit for
knowledge and expertise they have gained through
prior course work, independent study or work and
life experience.
Under 18
10%
30 years and older
29%
Over the years, the CLEP examinations have evolved
to keep pace with changing curricula and pedagogy.
Typically, the examinations represent material taught
in introductory college-level courses from all areas
of the college curriculum. Students may choose from
33 different subject areas in which to demonstrate
their mastery of college-level material.
18-22 years
39%
23-29 years
22%
* These data are based on 100% of CLEP test-takers who responded to this
survey question during their examinations.
2011-12 National CLEP Candidates by Gender
Today, more than 2,900 colleges and universities
recognize and grant credit for CLEP.
42%
Philosophy of CLEP
Promoting access to higher education is CLEP’s
foundation. CLEP offers students an opportunity to
demonstrate and receive validation of their
college-level skills and knowledge. Students who
achieve an appropriate score on a CLEP exam can
enrich their college experience with higher-level
courses in their major field of study, expand their
horizons by taking a wider array of electives and
avoid repetition of material that they already know.
58%
Computer-Based CLEP Testing
The computer-based format of CLEP exams allows
for a number of key features. These include:
• a variety of question formats that ensure effective
assessment
• real-time score reporting that gives students and
colleges the ability to make immediate creditgranting decisions (except College Composition,
which requires faculty scoring of essays twice a
month)
• a uniform recommended credit-granting score of
50 for all exams
• “rights-only” scoring, which awards one point per
correct answer
• pretest questions that are not scored but provide
current candidate population data and allow for
rapid expansion of question pools
CLEP Participants
CLEP’s test-taking population includes people of all
ages and walks of life. Traditional 18- to 22-year-old
students, adults just entering or returning to school,
home-schoolers and international students who need
to quantify their knowledge have all been assisted by
CLEP in earning their college degrees. Currently,
58 percent of CLEP’s test-takers are women and
51 percent are 23 years of age or older.
For over 30 years, the College Board has worked to
provide government-funded credit-by-exam
opportunities to the military through CLEP. Military
service members are fully funded for their CLEP exam
fees. Exams are administered at military installations
worldwide through computer-based testing programs
2
CLEP Exam Development
The Committee
Content development for each of the CLEP exams
is directed by a test development committee. Each
committee is composed of faculty from a wide
variety of institutions who are currently teaching
the relevant college undergraduate courses. The
committee members establish the test specifications
based on feedback from a national curriculum
survey; recommend credit-granting scores and
standards; develop and select test questions; review
statistical data and prepare descriptive material for
use by faculty (Test Information Guides) and students
planning to take the tests (CLEP Official Study Guide).
The College Board appoints standing committees of
college faculty for each test title in the CLEP battery.
Committee members usually serve a term of up to
four years. Each committee works with content
specialists at Educational Testing Service to establish
test specifications and develop the tests. Listed
below are the current committee members and their
institutional affiliations.
College faculty also participate in CLEP in other
ways: they convene periodically as part of
standard-setting panels to determine the
recommended level of student competency for the
granting of college credit; they are called upon to
write exam questions and to review forms and they
help to ensure the continuing relevance of the CLEP
examinations through the curriculum surveys.
Edward Wells,
Chair
Wilson College
Lucille Garmon
University of West Georgia
Nancy Morvillo
Florida Southern College
Susan Postawko
University of Oklahoma
The primary objective of the committee is to produce
tests with good content validity. CLEP tests must be
rigorous and relevant to the discipline and the
appropriate courses. While the consensus of the
committee members is that this test has high content
validity for a typical Natural Sciences course or
curriculum, the validity of the content for a specific
course or curriculum is best determined locally
through careful review and comparison of test
content, with instructional content covered in a
particular course or curriculum.
The Curriculum Survey
The first step in the construction of a CLEP exam is
a curriculum survey. Its main purpose is to obtain
information needed to develop test-content
specifications that reflect the current college
curriculum and to recognize anticipated changes in
the field. The surveys of college faculty are
conducted in each subject every three to five years
depending on the discipline. Specifically, the survey
gathers information on:
• the major content and skill areas covered in the
equivalent course and the proportion of the course
devoted to each area
• specific topics taught and the emphasis given to
each topic
• specific skills students are expected to acquire and
the relative emphasis given to them
• recent and anticipated changes in course content,
skills and topics
• the primary textbooks and supplementary learning
resources used
• titles and lengths of college courses that
correspond to the CLEP exam
The Committee Meeting
The exam is developed from a pool of questions
written by committee members and outside question
writers. All questions that will be scored on a CLEP
exam have been pretested; those that pass a rigorous
statistical analysis for content relevance, difficulty,
fairness and correlation with assessment criteria are
added to the pool. These questions are compiled by
test development specialists according to the test
specifications, and are presented to all the committee
members for a final review. Before convening at a
two- or three-day committee meeting, the members
have a chance to review the test specifications and
the pool of questions available for possible inclusion
in the exam.
3
At the meeting, the committee determines whether
the questions are appropriate for the test and, if not,
whether they need to be reworked and pretested
again to ensure that they are accurate and
unambiguous. Finally, draft forms of the exam are
reviewed to ensure comparable levels of difficulty and
content specifications on the various test forms. The
committee is also responsible for writing and
developing pretest questions. These questions are
administered to candidates who take the examination
and provide valuable statistical feedback on student
performance under operational conditions.
developing, administering and scoring the exams.
Effective July 2001, ACE recommended a uniform
credit-granting score of 50 across all subjects, with
the exception of four-semester language exams,
which represents the performance of students who
earn a grade of C in the corresponding college
course.
The American Council on Education, the major
coordinating body for all the nation’s higher education
institutions, seeks to provide leadership and a unifying
voice on key higher education issues and to influence
public policy through advocacy, research and program
initiatives. For more information, visit the ACE
CREDIT website at www.acenet.edu/acecredit.
Once the questions are developed and pretested,
tests are assembled in one of two ways. In some
cases, test forms are assembled in their entirety.
These forms are of comparable difficulty and are
therefore interchangeable. More commonly,
questions are assembled into smaller,
content-specific units called testlets, which can then
be combined in different ways to create multiple test
forms. This method allows many different forms to
be assembled from a pool of questions.
CLEP Credit Granting
CLEP uses a common recommended credit-granting
score of 50 for all CLEP exams.
This common credit-granting score does not mean,
however, that the standards for all CLEP exams are
the same. When a new or revised version of a test is
introduced, the program conducts a standard setting
to determine the recommended credit-granting score
(“cut score”).
Test Specifications
Test content specifications are determined primarily
through the curriculum survey, the expertise of the
committee and test development specialists, the
recommendations of appropriate councils and
conferences, textbook reviews and other appropriate
sources of information. Content specifications take
into account:
• the purpose of the test
• the intended test-taker population
• the titles and descriptions of courses the test is
designed to reflect
• the specific subject matter and abilities to be tested
• the length of the test, types of questions and
instructions to be used
A standard-setting panel, consisting of 15–20 faculty
members from colleges and universities across the
country who are currently teaching the course, is
appointed to give its expert judgment on the level of
student performance that would be necessary to
receive college credit in the course. The panel
reviews the test and test specifications and defines
the capabilities of the typical A student, as well as
those of the typical B, C and D students.* Expected
individual student performance is rated by each
panelist on each question. The combined average of
the ratings is used to determine a recommended
number of examination questions that must be
answered correctly to mirror classroom performance
of typical B and C students in the related course. The
panel’s findings are given to members of the test
development committee who, with the help of
Educational Testing Service and College Board
psychometric specialists, make a final determination
on which raw scores are equivalent to B and C levels
of performance.
Recommendation of the American
Council on Education (ACE)
The American Council on Education’s College
Credit Recommendation Service (ACE CREDIT)
has evaluated CLEP processes and procedures for
*Student performance for the language exams (French, German and Spanish)
is defined only at the B and C levels.
4
Natural Sciences
Description of the Examination
• Interpretation and comprehension of information
(about 20 percent of the examination) presented
in the form of graphs, diagrams, tables,
equations or verbal passages
• Qualitative and quantitative application of
scientific principles (about 40 percent of the
examination), including applications based on
material presented in the form of graphs,
diagrams, tables, equations or verbal passages;
more emphasis is given to qualitative than
quantitative applications
The Natural Sciences examination covers a wide
range of topics frequently taught in introductory
courses surveying both biological and physical
sciences at the freshman or sophomore level. Such
courses generally satisfy distribution or general
education requirements in science that usually are
not required of nor taken by science majors. The
Natural Sciences exam is not intended for those
specializing in science; it is intended to test the
understanding of scientific concepts that an adult
with a liberal arts education should have. It does not
stress the retention of factual details; rather, it
emphasizes the knowledge and application of the
basic principles and concepts of science, the
comprehension of scientific information, and the
understanding of issues of science in contemporary
society.
The subject matter of the Natural Sciences
examination is drawn from the following topics.
The percentages next to the main topics indicate the
approximate percentage of exam questions on that
topic.
The primary objective of the examination is to give
candidates the opportunity to demonstrate a level of
knowledge and understanding expected of college
students meeting a distribution or general education
requirement in the natural sciences. An institution
may grant up to six semester hours (or the equivalent)
of credit toward fulfillment of such a requirement for
satisfactory scores on the examination. Some may
grant specific course credit, on the basis of the total
score for a two-semester survey course covering
both biological and physical sciences.
The examination contains approximately
120 questions to be answered in 90 minutes.
Some of these are pretest questions that will not
be scored. Any time candidates spend on tutorials
and providing personal information is in addition
to the actual testing time.
Biological Science (50%)
10%
Origin and evolution of life,
classification of organisms
10%
Cell organization, cell division,
chemical nature of the gene,
bioenergetics, biosynthesis
20%
Structure, function and
development in organisms; patterns
of heredity
10%
Concepts of population biology
with emphasis on ecology
Physical Science (50%)
7%
Atomic and nuclear structure and
properties, elementary particles,
nuclear reactions
10%
Chemical elements, compounds
and reactions, molecular structure
and bonding
12%
Heat, thermodynamics and states
of matter; classical mechanics;
relativity
4%
Electricity and magnetism, waves,
light and sound
7%
The universe: galaxies, stars, the
solar system
10%
The Earth: atmosphere,
hydrosphere, structure features,
geologic processes and history
Knowledge and Skills Required
The Natural Sciences examination requires
candidates to demonstrate one or more of the
following abilities in the approximate proportions
indicated.
• Knowledge of fundamental facts, concepts and
principles (about 40 percent of the examination)
5
N A T U R A L
S C I E N C E S
Questions 3–5
The examination includes some questions that are
interdisciplinary and cannot be classified in one of
the listed categories. Some of the questions cover
topics that overlap with those listed previously,
drawing on areas such as history and philosophy
of science, scientific methods, science applications
and technology, and the relationship of science
to contemporary problems of society, such as
environmental pollution and depletion of natural
resources. Some questions are laboratory oriented.
(A)
(D)
0
0
(E)
(B)
Sample Test Questions
The following sample questions do not appear on
an actual CLEP examination. They are intended
to give potential test-takers an indication of the
format and difficulty level of the examination and
to provide content for practice and review. Knowing
the correct answers to all of the sample questions is
not a guarantee of satisfactory performance on the
exam.
0
0
(C)
0
Directions: Each group of questions that follow
consists of five lettered choices followed by a list of
numbered phrases or sentences. For each numbered
phrase or sentence, select the one choice that is most
clearly related to it. Each choice may be used once,
more than once, or not at all in each group.
3. A sample of gas remains at constant temperature.
Vertical axis: Volume of the sample
Horizontal axis: Pressure on the sample
4. An object moves at constant speed.
Vertical axis: Distance traveled since time t = 0
Horizontal axis: Time
Questions 1–2
(A) Cell wall
(B) Cell membrane
(C) Nucleus
(D) Mitochondrion
(E) Ribosome
5. A constant unbalanced force acts on an object.
Vertical axis: Acceleration of the object
Horizontal axis: Time
Questions 6–7
(A) Tuberculosis
(B) Phenylketonuria
(C) Huntington disease
(D) Cystic fibrosis
(E) Tay-Sachs disease
1. The chief site of energy production in the cell
2. The site of protein synthesis in the cell
6. The disease that is NOT genetically inherited
7. The disease that can be controlled merely
through regulation of diet
6
N A T U R A L
S C I E N C E S
Directions: Each of the questions or incomplete
statements below is followed by five suggested
answers or completions. Select the one that is best
in each case.
Questions 10–11
In fruit flies, “straight wings” (S) is dominant
over “curly wings” (s), and gray body color (G)
is dominant over black body color (g). A straightwinged female with gray body color was mated
with a straight-winged male with black body color
and the following ratios of offspring resulted. The
experiment was conducted at 25°C.
8. As a direct result of photosynthesis, energy is
stored in molecules of which of the following?
(A) RNA
(B) DNA
(C) C6H12O6 (glucose)
(D) H2O
(E) CO2
9. A person whose gallbladder has been removed
has a decreased ability to store bile and therefore
to digest
Ratio
Phenotype
3/8
straight-winged; gray body color
3/8
straight-winged; black body color
1/8
curly-winged; gray body color
1/8
curly-winged; black body color
10. The data above suggest that the genotype of the
male parent is
(A) fats
(B) starches
(C) sugars
(D) proteins
(E) vitamins
(A) SsGg
(B) SSGg
(C) ssgg
(D) Ssgg
(E) ssGg
11. The data above suggest that the genotype of
the offspring with curly wings and black body
color is
(A) SsGg
(B) SSGg
(C) ssgg
(D) Ssgg
(E) ssGg
12. The classification characteristics that define the
genus of an animal or a plant are usually more
general than those defining
(A) a class
(B) an order
(C) a species
(D) a family
(E) a phylum
7
N A T U R A L
S C I E N C E S
17. In embryonic origin, nerve cells are most
similar to
13. Hard water is undesirable and is often softened
because hard water
(A) epidermal cells
(B) bone cells
(C) red blood cells
(D) liver cells
(E) reproductive cells
(A) is too viscous for regular uses
(B) contains trace amounts of toxic substances
(C) forms insoluble precipitates when boiled or
when used with soap
(D) cannot be used efficiently by the body due
to dissolved impurities
(E) evaporates more rapidly than soft water
18. In the name Homo sapiens, the word sapiens
refers to the
14. Which of the following adaptations is more
likely to be found in the leaves of desert plants
than in those of plants that grow in moist
regions?
(A) species
(B) family
(C) class
(D) genus
(E) order
(A) Stomata mostly on upper leaf surface
(B) A thin, transparent cuticle
(C) A smooth leaf surface free of hairs
(D) A thickened epidermis and cuticle
(E) A loosely packed mesophyll layer
15. If all the xylem from a section of tree trunk
could be removed, which of the following
would most likely happen first?
(A) Food could not pass from the leaves to
the roots.
(B) The roots would be unable to transfer any
stored food to the spring buds.
(C) The leaves would be unable to get any
carbon dioxide.
(D) The roots would be unable to store food.
(E) The leaves would be unable to get sufficient
water.
19. A student placed a sprig of green water plant
under a funnel in a glass vessel full of water
and then placed a test tube full of water mouthdownward over the stem of the funnel. After the
setup had been exposed to sunlight for several
hours, the student tested a gas that had collected
in the test tube and concluded that the plant had
produced oxygen. The results of this experiment
could have been interpreted more satisfactorily if
16. Whereas the ultimate source of energy for most
organisms is sunlight, the immediate source is
(A) chemical
(B) electrical
(C) thermal
(D) gravitational
(E) radiant
(A) the water had been tested for carbon dioxide
(B) only the leaves of the plant had been used
(C) air had been forced through the water
(D) the plant had not been exposed to sunlight
(E) a similar experiment had been set up without
sunlight
8
N A T U R A L
S C I E N C E S
24. In many cultivated plants (such as oranges,
bananas, and potatoes), favorable characteristics
often are created by careful genetic crosses. Of
the following, which would be the best way to
maintain the traits of a new variety with
favorable characteristics?
20. Which of the following best completes the
statement below?
Among multicellular animals, the insects
exhibit the greatest diversity of life-forms;
therefore ______.
(A) the total number of insect species is limited
(B) the presence of wings on an insect is
probably an evolutionary error
(C) insects probably occupy the greatest number
of niches
(D) insect control by human beings is simplified
(E) any genetic mutation in fruit flies is likely to
escape detection
(A) Selfing individuals of this new variety (i.e.,
crossing the offspring of one parental plant)
(B) Artificially pollinating wild varieties with
pollen from the new variety
(C) Artificially pollinating the new variety with
pollen from wild varieties
(D) Crossing the new variety with a variety that
was homozygous recessive for all traits of
concern
(E) Vegetative reproduction of the new variety
21. The percentage of phosphates in commercial
detergents was reduced primarily because
phosphates were shown to
25. In mammals, insulin is produced in which of the
following structures?
(A) be less effective cleaning agents than most
other compounds
(B) build up in animal tissues and cause sterility
(C) cause cancer in animals
(D) cause birth defects in animals
(E) increase the growth rates of algae in lakes
and rivers
(A) Pancreas
(B) Liver
(C) Salivary glands
(D) Hypothalamus
(E) Pituitary gland
26. Which of the following occurs during anaphase I
of meiosis?
22. Carbohydrates are most commonly stored in
plants in the form of
(A) The sister chromatids are pulled to opposite
poles of the spindle.
(B) The spindle apparatus forms.
(C) The nuclear envelope disintegrates.
(D) The centromeres replicate.
(E) The homologous pairs of chromosomes
separate.
(A) starch
(B) cellulose
(C) lactose
(D) ribose
(E) sucrose
23. A father will transmit the genes of his
Y chromosome to
27. All living cells have which of the following
structures?
(A) one-half of his sons only
(B) one-half of his daughters only
(C) all of his sons only
(D) all of his daughters only
(E) none of his sons
(A) Endoplasmic reticulum
(B) Nucleus
(C) Plasma membrane
(D) Cilia
(E) Vacuole
9
N A T U R A L
S C I E N C E S
32. Which of the following most directly leads
to changes in cellular specialization during
embryonic development?
28. Digestion of proteins in mammals begins in
which of the following organs?
(A) Mouth
(B) Stomach
(C) Small intestine
(D) Colon
(E) Gallbladder
(A) Meiosis in the embryo’s cells
(B) Changes in the environmental stimuli the
embryo experiences in the uterus
(C) Formation of the placenta
(D) An increase in the amount of DNA in the
embryo due to replication
(E) Changes in gene expression
29. Which of the following terrestrial biomes
typically has the greatest species diversity?
33. Which of the following animals is most closely
related to the cheetah?
(A) Tundra
(B) Taiga
(C) Deciduous forest
(D) Chaparral
(E) Tropical rain forest
(A) Chicken
(B) Alligator
(C) Frog
(D) Squirrel
(E) Eagle
30. Which of the following instruments would be
most useful for studying the internal structure
of a chloroplast?
34. Which of the following organisms typically
transmits the West Nile virus to humans?
(A) Transmission electron microscope
(B) Scanning electron microscope
(C) Compound light microscope
(D) Dissecting microscope
(E) Phase-contrast microscope
(A) Housefly
(B) Tsetse fly
(C) Mosquito
(D) Tick
(E) Mouse
31. A hawk can have which of the following
ecological roles?
35. A photosynthetic eukaryotic cell typically
contains
I. Primary consumer
II. Secondary consumer
III. Tertiary consumer
(A) chloroplasts only
(B) mitochondria only
(C) both chloroplasts and mitochondria
(D) either chloroplasts or mitochondria, but
never both at once
(E) neither chloroplasts nor mitochondria
(A) I only
(B) II only
(C) III only
(D) I and II only
(E) II and III only
10
N A T U R A L
S C I E N C E S
40. Which of the following best describes the
principal way in which Earth’s atmosphere
is heated?
36. A theory fails to meet the criteria of scientific
methodology if
(A) it is unpopular
(B) it contradicts other theories
(C) it has not been conclusively proved
(D) it has not been stated in mathematical terms
(E) no experiments can be designed to test it
37. Dark lines in the Sun’s spectrum are explained as
resulting from
(A) emission of radiation of certain frequencies
from the Sun’s atmosphere
(B) absorption of energy by atoms in the outer
layers of the Sun
(C) radiation of ultraviolet light from sunspots
(D) continuous radiation from the corona
(E) x-rays emanating from the Sun’s atmosphere
38. Scientists estimate the age of the Sun to be
about
(A) 100 billion years
(B) 25 billion years
(C) 14 billion years
(D) 4.6 billion years
(E) 3.8 billion years
(A) Heat flows from the center of Earth and is
conducted through the ground to the air.
(B) The atmosphere absorbs short-wave
radiation from the Sun as the Sun’s rays
pass through it.
(C) Earth absorbs short-wave radiation from the
Sun and reradiates long-wave radiation,
which is absorbed by the atmosphere.
(D) The air absorbs short-wave radiation from
the Sun after the radiation has been reflected
by the clouds.
(E) Warm air rises and cold air sinks and, as it
sinks, is warmed by compression.
41. Most of Earth’s water exists in
(A) the oceans
(B) the atmosphere
(C) groundwater
(D) lakes and rivers
(E) polar ice caps
42. If the present electric power needs of the
United States are to be provided by solar power
only, all the sunlight incident on which of the
following areas must be collected? (Assume
100 percent efficiency.)
39. Sunspots on the surface of the Sun are correlated
with which of the following?
(A) Relatively low temperatures compared with
the surrounding surface
(B) Relatively high temperatures compared with
the surrounding surface
(C) Periods of low solar activity
(D) Fusion of helium nuclei rather than
hydrogen nuclei
(E) The warming of ocean surface waters in the
eastern Pacific (El Niño)
11
(A) A small percent of the area in the
United States
(B) All of the area in the United States
(C) All of the area in the Western Hemisphere
(D) All of the area of Earth
(E) All of the area of Earth plus some in
outer space
N A T U R A L
S C I E N C E S
47. The half-life of 146C is 5,600 years. Which of the
following statements about a 10-gram sample of
14
6 C is correct?
43. Which of the following natural resources is
NOT a fossil fuel?
(A) Uranium
(B) Natural gas
(C) Petroleum
(D) Anthracite coal
(E) Bituminous coal
(A) The radioactive decay of the sample will be
complete after 5,600 years.
(B) The 146C sample will start radioactive decay
after 5,600 years.
(C) A time of 5,600 years has been required to
produce this sample of 146C in nature.
(D) After 5,600 years the sample will contain
only 5 grams of 146C.
(E) After 11,200 years the sample will not
contain any 146C.
44. All of the following geologic time intervals are
characterized correctly EXCEPT
(A) Cambrian period . . . age of birds
(B) Carboniferous period . . . age of amphibians
(C) Devonian period . . . age of fishes
(D) Cenozoic era . . . age of mammals
(E) Mesozoic era . . . age of dinosaurs
48. Impact craters dominate the Moon’s surface,
yet are rare on Earth’s surface. Reasons for this
difference include which of the following?
I. The Moon has no atmosphere.
II. The Moon is geologically inactive.
III. The Moon is much older.
45. Which of the following is the farthest, on
average, from Earth?
(A) Andromeda galaxy
(B) Halley’s comet
(C) Jupiter
(D) Sirius
(E) Uranus
(A) I only
(B) II only
(C) I and II only
(D) II and III only
(E) I, II, and III
CaO + CO2 → CaCO3
49. At a fixed pressure, when the temperature of a
gas sample increases, its volume increases. This
relationship between the temperature and the
volume of a gas is best described as which of
the following?
46. What mass of CaO is needed to absorb
22 grams of CO2 according to the balanced
chemical equation above? (Molar masses:
CaO = 56 g/mol, CO2 = 44 g/mol)
(A) Direct proportion
(B) Inverse proportion
(C) Limiting ratio
(D) Hyperbolic function
(E) Logarithmic function
(A) 112 g
(B) 100 g
(C) 56 g
(D) 28 g
(E) 22 g
12
N A T U R A L
S C I E N C E S
50. The notation 1s2 2s2 2p4 represents
53. Of the following planets that are visible with the
naked eye—Venus, Mars, Jupiter, and Saturn—
only Venus has an orbit smaller than that of
Earth. This means that Venus
(A) a noble gas
(B) an atomic nucleus
(C) an element with atomic mass 8
(D) an element with atomic number 8
(E) an element with an oxidation state of 4
(A) is seen only in the morning or the evening sky
(B) can be seen in the sky near midnight more
often than at other times
(C) can rarely be seen at all
(D) has an orbit that is more elliptical than that
of Earth
(E) has a longer year than Earth
51. Which of the following molecules can have
more than one equivalent Lewis structure?
(A) H
O
(B) H C
(C) O
O
H
54. Which of the following is NOT generally true
of metals?
C H
(A) They are usually solid at room temperature.
(B) They are good conductors of heat and
electricity.
(C) They easily form negative ions.
(D) They have luster.
(E) They can be hammered into sheets or rolled
into wires.
O
(D) H N H
H
H
(E) H C O H
H
55. Within molecules of a compound, atoms are held
together by chemical bonds that are primarily
(A) thermal
(B) frictional
(C) gravitational
(D) electrostatic
(E) magnetic
52. In old-fashioned flashbulbs, light was produced
by the reaction of magnesium metal, Mg, sealed
in the bulb with oxygen gas, O2. After the flash,
the mass of the sealed bulb was
(A) definitely greater than it was before use
(B) definitely smaller than it was before use
(C) essentially the same as it was before use
(D) greater or smaller depending on the amount
of O2 consumed
(E) greater or smaller depending on the amount
of light produced
56. An unsorted mixture of clay, boulders, sand, and
silt would most likely be deposited from which
of the following?
(A) Glacial ice
(B) Subsurface water
(C) Streams
(D) Waves
(E) Wind
13
N A T U R A L
S C I E N C E S
60. Which of the following correctly identifies the
131
constituents of an atom of the isotope 53 I ?
57. Valleys with U-shaped cross sections are the
result of erosion by which of the following?
(A) Glaciers
(B) Perennial streams
(C) Intermittent streams
(D) Mudflows
(E) Wind
d
(A)
(B)
(C)
(D)
(E)
Protons
Neutrons
Electrons
53
78
53
78
131
78
53
78
131
53
78
78
53
78
53
d
61. Which of the following types of electromagnetic
radiation has photons of the LEAST energy?
X
(A) Visible light
(B) Ultraviolet light
(C) Microwaves
(D) Gamma radiation
(E) Radio waves
Y
58. The balance shown above is in equilibrium at
Earth’s surface, and the two arms have the same
length d. Thus the two objects, X and Y (not
necessarily drawn to scale), must have identical
(A) densities
(B) masses
(C) shapes
(D) specific gravities
(E) volumes
62. The atomic mass of carbon is 12 and the atomic
mass of hydrogen is 1. What is the percent by
mass of carbon in methane gas, CH4?
(A) 20%
(B) 25%
(C) 50%
(D) 75%
(E) 80%
59. On a global basis, for which of the following
activities is the most water used each day?
(A) Crop irrigation
(B) Cooling in power plants
(C) Commercial laundering
(D) Manufacturing of textiles
(E) Production of steel
63. Southern California experienced an earthquake
that registered magnitude 3.5 on the Richter
scale. One month later the same area
experienced an earthquake that registered 5.5.
About how many times as much energy was
released by the magnitude 5.5 earthquake than
by the magnitude 3.5 earthquake?
(A)
2
(B)
10
(C) 200
(D) 1,000
(E) 2,000
14
N A T U R A L
S C I E N C E S
64. The study of which of the following would likely
be the most helpful in providing information
about the composition of Earth’s upper mantle?
(A) Temperatures of hot springs
(B) Size of vesicles in basalt flows
(C) Xenolith inclusions in igneous rocks
(D) Carbonate sediments from the ocean floor
(E) Minerals formed through contact
metamorphism
65. Which of the following are found in greater
number in the nuclei of carbon-14 atoms than
in the nuclei of carbon-12 atoms?
(A) Alpha particles
(B) Positrons
(C) Neutrons
(D) Protons
(E) Electrons
66. Which of the following best describes the
motion of winds within large storm systems
in the Northern Hemisphere?
67. The amount of heat energy released when a
certain type of candle is burned is 48,000 joules
per gram of wax consumed. Which of the
following expressions is equal to the number
of grams of wax that need to be burned in order
to raise the temperature of 500 grams of water
from 20°C to 30°C, assuming all the heat
released goes into heating the water? (The
specific heat of water is 4.19 J/g°C.)
(A)
(48, 000)(10)(4.19)
500
(B)
(48, 000)(4.19)
(500)(10)
(C)
(4.19)(10)(500)
48, 000
(D)
(4.19)(500)
(10)(48, 000)
(E)
(30)(4.19)(500)
(20)(48, 000)
68. Which of the following types of radiation
is typically produced in the laboratory by a
high-voltage electron beam impacting a
metallic target?
(A) North to south
(B) West to east
(C) Southwest to northeast
(D) Clockwise
(E) Counterclockwise
(A) Primary cosmic radiation
(B) X-ray radiation
(C) Neutron radiation
(D) Ultraviolet radiation
(E) Beta radiation
15
N A T U R A L
S C I E N C E S
Questions 69–71
71. Which of the following would most likely
increase the effectiveness of the hydrogen gas
reducing the copper(II) oxide?
CuO + H2 → Cu + H2O
(A) Heating the test tube
(B) Cooling the test tube
(C) Putting the test tube under reduced pressure
(D) Filling the test tube with dilute HCl solution
(E) Filling the test tube with dilute NaOH
solution
The drawing below depicts an apparatus for
reducing copper(II) oxide to the metal by the
reaction above.
Thistle Tube
Test Tube
Drying Tube
72. Which of the following typically occurs when a
forested watershed is clear-cut?
Rubber
Stoppers
Copper(II)
Oxide
(A) Annual rainfall increases.
(B) Soil erosion increases.
(C) The water temperature in streams decreases.
(D) The sediment load in streams decreases.
(E) Atmospheric concentration of O2 increases.
250-mL. Erlenmeyer Flask
Zinc
69. In order to produce a stream of hydrogen gas
for this reaction, one should add which of the
following through the thistle tube?
73. Which characteristic of a star most directly
relates to the likelihood of that star’s eventually
becoming a black hole?
(A) Water
(B) Dilute hydrochloric acid
(C) Dilute copper(II) sulfate solution
(D) Hydrogen peroxide
(E) Dilute ammonia solution
(A) Apparent magnitude
(B) Absolute magnitude
(C) Surface temperature
(D) Diameter
(E) Mass
70. After the production of hydrogen gas starts,
withdrawing the thistle tube would result in
which of the following?
(A) Moisture would collect in the flask.
(B) The evolution of hydrogen gas would stop.
(C) Much hydrogen gas would escape without
coming in contact with the copper oxide.
(D) Air would enter the flask faster than
hydrogen gas would be evolved.
(E) The rate of production of hydrogen gas
would increase.
16
N A T U R A L
S C I E N C E S
77. Which of the following is true about cells that
lose the ability to regulate cell division?
74. How many joules of energy are absorbed by a
20.0 g sample of water as the temperature of
the sample is raised from 273 K to 283 K? (The
specific heat capacity of water is 4.2 J g−1K−1.)
(A) They commonly have two nuclei.
(B) They can develop into cancer cells.
(C) They will divide forever using ribosomes.
(D) They are missing key genes that separate
chromatids.
(E) They cannot be used for drug research.
(A)
42 J
(B)
84 J
(C) 200 J
(D) 840 J
(E) 4,200 J
78. Which of the following is considered necessary
for a planet to support life?
← N2O4(g)
2 NO2(g) →
75. The equation above represents a system that has
reached a state of chemical equilibrium. Which
of the following is a true statement about the
system?
(A) All chemical reaction rates have dropped to
zero.
(B) The system will eventually contain only
N2O4 molecules.
(C) The concentration of NO2(g) must be twice
that of N2O4(g).
(D) The concentration of NO2(g) must be less
than that of N2O4(g).
(E) N2O4 molecules are being consumed as fast
as they are produced.
(A) Oxygen gas (O2)
(B) RNA
(C) Liquid water
(D) Nitrogen gas (N2)
(E) Bicarbonate
79. In a healthy human, which of the following
should be free of microbes?
(A) Mouth
(B) Large intestine
(C) Stomach
(D) Spinal fluid
(E) Skin
80. What is the mass of chlorine in 5.87 x 1024
molecules of SOCl2 ?
76. Which of the following best describes antibiotic
resistance?
(A) It is a condition that causes humans to
become resistant to antibiotics.
(B) It is caused by overuse of antibiotics, which
allows for selection of resistant bacteria.
(C) It causes organisms to contract viral
infections.
(D) It is a problem only in developing countries.
(E) It is a treatment for infections that results in
a resistant immune system in an organism.
17
(A) 9.5 g
(B) 35 g
(C) 54.6 g
(D) 691 g
(E) 975 g
81. An atom whose ground-state electron
configuration ends with …..p5 is
(A) a halogen
(B) a noble gas
(C) an alkali metal
(D) an alkaline earth metal
(E) a member of the oxygen family
N A T U R A L
S C I E N C E S
84. Which of the following is true about a sinking
parcel of air?
82. Water has a higher boiling point than hydrogen
sulfide because water has stronger
(A) It will decrease in pressure.
(B) It will expand and cool.
(C) It will be unstable.
(D) It will compress and warm.
(E) It will form clouds.
(A) ionic bonds
(B) covalent bonds
(C) hydrogen bonds
(D) ion-dipole forces
(E) London dispersion forces
85. Pluto is not categorized as a planet by scientists
because
83. Heat can be transferred from one place to
another by which of the following?
(A) it is smaller than Earth’s Moon
(B) it cannot clear debris from its orbit
(C) its orbit crosses through the orbit of
Neptune
(D) it has a large moon
(E) it has an unstable atmosphere
I. Conduction
II. Convection
III. Radiation
(A) I only
(B) II only
(C) III only
(D) I and II only
(E) I, II, and III
18
N A T U R A L
S C I E N C E S
Study Resources
Most textbooks used in college-level natural
sciences courses cover the topics in the outline
given earlier, but the approaches to certain topics
and the emphases given to them may differ. To
prepare for the Natural Sciences exam, it is
advisable to study one or more college textbooks
(selecting at least one biological science and one
physical science textbook), which can be found in
most college bookstores. When selecting a textbook,
check the table of contents against the knowledge
and skills required for this test.
If candidates maintain an interest in scientific
issues; read science articles in newspapers and
magazines; watch educational television programs
on scientific topics; or work in fields that require
a knowledge of certain areas of science, such as
nursing and laboratory work, they will probably
be knowledgeable about many of the topics included
on the Natural Sciences exam.
Visit www.collegeboard.org/clepprep for additional
science resources. You can also find suggestions for
exam preparation in Chapter IV of the Official Study
Guide. In addition, many college faculty post their
course materials on their schools’ websites.
19
Answer Key
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
D
E
C
D
E
A
B
C
A
D
C
C
C
D
E
A
A
A
E
C
E
A
C
E
A
E
C
B
E
A
E
E
D
C
C
E
B
D
A
C
A
A
A
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.
85.
A
A
D
D
C
A
D
C
C
A
C
D
A
A
B
A
C
E
D
D
C
C
E
C
B
B
C
A
B
E
D
E
B
B
C
D
D
A
C
E
D
B
N A T U R A L
Test Measurement Overview
Format
There are multiple forms of the computer-based test,
each containing a predetermined set of scored
questions. The examinations are not adaptive. There
may be some overlap between different forms of a
test: any of the forms may have a few questions,
many questions, or no questions in common. Some
overlap may be necessary for statistical reasons.
In the computer-based test, not all questions
contribute to the candidate’s score. Some of the
questions presented to the candidate are being
pretested for use in future editions of the tests and
will not count toward his or her score.
Scoring Information
CLEP examinations are scored without a penalty for
incorrect guessing. The candidate’s raw score is
simply the number of questions answered correctly.
However, this raw score is not reported; the raw
scores are translated into a scaled score by a process
that adjusts for differences in the difficulty of the
questions on the various forms of the test.
S C I E N C E S
credit-granting scores are based upon the judgments
of a panel of experts currently teaching equivalent
courses at various colleges and universities. These
experts evaluate each question in order to determine
the raw scores that would correspond to B and C
levels of performance. Their judgments are then
reviewed by a test development committee, which, in
consultation with test content and psychometric
specialists, makes a final determination. The
standard-setting study is described more fully in the
earlier section entitled “CLEP Credit Granting” on
page 4.
Panel members participating in the most recent study
were:
Joseph Allen
Brenda Alston-Mills
Bruce Callen
Amber Charlebois
Thomas Cobb
Jean DeSaix
Norman Derby
Ginger Fisher
Amy Gort
Scaled Scores
Terry Jones
The scaled scores are reported on a scale of 20–80.
Because the different forms of the tests are not
always exactly equal in difficulty, raw-to-scale
conversions may in some cases differ from form to
form. The easier a form is judged to be, the higher
the raw score required to attain a given scaled score.
Table 1 indicates the relationship between number
correct (raw score) and scaled score across all forms.
Philip Keller
Frank Kuserk
Jorge Lopez
Victor Okereke
Susan Postawko
Zachary Senwo
Rainy Shorey
Linda Wozniewski
The Recommended Credit-Granting
Score
Table 1 also indicates the recommended
credit-granting score, which represents the
performance of students earning a grade of C in the
corresponding course. The recommended B-level
score represents B-level performance in equivalent
course work. These scores were established as the
result of a Standard Setting Study, the most recent
having been conducted in 2006. The recommended
Concord University
North Carolina State University
Drury University
William Patterson University
Bowling Green State University
University of North Carolina —
Chapel Hill
Bennington College
Wilson College
Concordia University —
St. Paul
California State University —
Stanislaus
University of Arizona
Moravian College
University of Texas — El Paso
SUNY Morrisville State College
University of Oklahoma
Alabama A&M University
Ferris State University
Indiana University — Northwest
After the recommended credit-granting scores are
determined, a statistical procedure called scaling is
applied to establish the exact correspondences
between raw and scaled scores. Note that a scaled
score of 50 is assigned to the raw score that
corresponds to the recommended credit-granting
score for C-level performance, and a high but usually
less than perfect raw score is selected and assigned a
scaled score of 80.
20
Table 1: Natural Sciences
Interpretive Score Data
American Council on Education (ACE) Recommended Number of Semester Hours of Credit: 6
Course Grade
B
C
Scaled Score
Number Correct
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50*
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
100
98-99
96-97
95-96
93-94
91-92
90-91
88-89
87-88
85-86
83-85
82-83
80-82
79-80
77-78
75-77
74-75
72-74
71-72
69-71
68-69
66-68
65-66
63-65
61-63
60-62
58-60
57-58
55-57
54-55
52-54
51-52
49-51
48-49
46-48
45-46
43-45
42-43
40-42
38-40
37-38
35-37
34-35
32-34
31-32
29-31
28-29
26-28
24-26
23-25
21-23
20-21
18-20
17-18
15-17
13-15
12-14
10-12
9-10
7-9
0-7
*Credit-granting score recommended by ACE.
Note: The number-correct scores for each scaled score on different forms may vary depending on form difficulty.
21
N A T U R A L
S C I E N C E S
Validity
Reliability
Validity is a characteristic of a particular use of the
test scores of a group of examinees. If the scores are
used to make inferences about the examinees’
knowledge of a particular subject, the validity of the
scores for that purpose is the extent to which those
inferences can be trusted to be accurate.
The reliability of the test scores of a group of
examinees is commonly described by two statistics:
the reliability coefficient and the standard error of
measurement (SEM). The reliability coefficient is
the correlation between the scores those examinees
get (or would get) on two independent replications
of the measurement process. The reliability
coefficient is intended to indicate the
stability/consistency of the candidates’ test scores,
and is often expressed as a number ranging from
.00 to 1.00. A value of .00 indicates total lack of
stability, while a value of 1.00 indicates perfect
stability. The reliability coefficient can be interpreted
as the correlation between the scores examinees
would earn on two forms of the test that had no
questions in common.
One type of evidence for the validity of test scores is
called content-related evidence of validity. It is
usually based upon the judgments of a set of experts
who evaluate the extent to which the content of the
test is appropriate for the inferences to be made
about the examinees’ knowledge. The committee
that developed the CLEP Natural Sciences
examination selected the content of the test to reflect
the content of Natural Sciences courses at most
colleges, as determined by a curriculum survey.
Since colleges differ somewhat in the content of the
courses they offer, faculty members should, and are
urged to, review the content outline and the sample
questions to ensure that the test covers core content
appropriate to the courses at their college.
Another type of evidence for test-score validity is
called criterion-related evidence of validity. It
consists of statistical evidence that examinees who
score high on the test also do well on other measures
of the knowledge or skills the test is being used to
measure. Criterion-related evidence for the validity
of CLEP scores can be obtained by studies
comparing students’ CLEP scores with the grades
they received in corresponding classes, or other
measures of achievement or ability. CLEP and the
College Board conduct these studies, called
Admitted Class Evaluation Service or ACES, for
individual colleges that meet certain criteria at the
college’s request. Please contact CLEP for more
information.
Statisticians use an internal-consistency measure to
calculate the reliability coefficients for the CLEP
exam. This involves looking at the statistical
relationships among responses to individual
multiple-choice questions to estimate the reliability
of the total test score. The formula used is known as
Kuder-Richardson 20, or KR-20, which is equivalent
to a more general formula called coefficient alpha.
The SEM is an index of the extent to which students’
obtained scores tend to vary from their true scores.1
It is expressed in score units of the test. Intervals
extending one standard error above and below the
true score (see below) for a test-taker will include
68 percent of that test-taker’s obtained scores.
Similarly, intervals extending two standard errors
above and below the true score will include
95 percent of the test-taker’s obtained scores. The
standard error of measurement is inversely related to
the reliability coefficient. If the reliability of the test
were 1.00 (if it perfectly measured the candidate’s
knowledge), the standard error of measurement
would be zero.
Scores on the CLEP examination in Natural
Sciences are estimated to have a reliability
coefficient of 0.91. The standard error of
measurement is 2.83 scaled-score points.
1
True score is a hypothetical concept indicating what an individual’s score on a
test would be if there were no errors introduced by the measuring process. It is
thought of as the hypothetical average of an infinite number of obtained scores
for a test-taker with the effect of practice removed.
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