Updated 2026 | 190+ Questions and Answers | Western Governors
University C165 Objective Assessment Study Guide, Practice Exam,
Comprehensive Review, Exam Prep Test Bank, Scientific Inquiry, Physics
Concepts, Chemistry Principles, Earth Science, Astronomy, Energy and
Matter, Motion and Forces, Weather and Climate Systems, Detailed
Rationales and Complete Revision Material
Question 1: What is the study of forces, energy, and motion called?
A. Chemistry
B. Earth science
C. Astronomy
D. Physics
CORRECT ANSWER: D. Physics
Rationale:Physics is the branch of physical science focused on forces, energy, and
motion, encompassing the fundamental laws governing the physical universe .
Question 2: Which branch of physical science is primarily concerned with the study
of atoms, molecules, and their interactions?
A. Physics
B. Chemistry
C. Earth science
D. Astronomy
CORRECT ANSWER: B. Chemistry
Rationale:Chemistry is the study of matter at the atomic and molecular level, including
its structure, properties, and the reactions that transform substances .
Question 3: Earth science is best described as the study of:
A. The universe and celestial bodies
B. Forces and energy
C. The Earth's structure, composition, and the processes that change it
D. The properties of atoms and molecules
CORRECT ANSWER: C. The Earth's structure, composition, and the processes that
change it
Rationale:Earth science focuses on the Earth system, including its geology,
atmosphere, and oceans, and the processes that shape its surface and interior .
Question 4: A student notices that a metal spoon left in a hot cup of coffee
becomes warm. The student proposes that heat is transferred from the coffee to
the spoon. Which type of scientific idea is this proposal?
,A. Law
B. Theory
C. Hypothesis
D. Observation
CORRECT ANSWER: C. Hypothesis
Rationale:A hypothesis is a testable, proposed explanation for an observation. The
student's explanation for why the spoon warms can be tested through further
experimentation .
Question 5: Which of the following is an example of a scientific law?
A. Objects with mass attract each other.
B. The Earth revolves around the Sun because of gravity.
C. Force equals mass times acceleration (F = ma).
D. All living things are made of cells.
CORRECT ANSWER: C. Force equals mass times acceleration (F = ma).
Rationale:A scientific law is a concise, often mathematical, statement of a
fundamental relationship in nature. F=ma, Newton's second law of motion, is a prime
example .
Question 6: A conceptual model is BEST described as:
A. A physical replica of an object.
B. A set of equations that predict outcomes.
C. A verbal, graphical, or diagrammatic explanation of how a system works.
D. A statement that has been proven true.
CORRECT ANSWER: C. A verbal, graphical, or diagrammatic explanation of how a
system works.
Rationale:Conceptual models are representations of ideas or systems using words,
diagrams, flowcharts, or other non-tangible means to explain structure and
relationships .
Question 7: A scientist measures the mass of a rock three times and gets 5.2 g, 5.3
g, and 5.1 g. The true mass is 5.0 g. Which statement best describes these
measurements?
A. Accurate but not precise
B. Precise but not accurate
C. Both accurate and precise
D. Neither accurate nor precise
CORRECT ANSWER: B. Precise but not accurate
,Rationale:The measurements are precise because they are all close to each other.
However, they are not accurate because they are consistently higher than the true
value, showing a systematic error .
Question 8: A scientist wants to test the effect of light intensity on plant growth.
What is the dependent variable?
A. Light intensity
B. Plant growth (e.g., height)
C. Type of plant
D. Amount of water
CORRECT ANSWER: B. Plant growth (e.g., height)
Rationale:The dependent variable is the factor that is measured in an experiment; it
"depends" on the changes made to the independent variable. In this case, plant growth
is measured in response to changes in light intensity .
Question 9: The independent variable in an experiment is:
A. The variable that is measured
B. The variable that is changed or controlled by the experimenter
C. The variable that remains constant
D. The variable that responds to the change
CORRECT ANSWER: B. The variable that is changed or controlled by the
experimenter
Rationale:The independent variable is the factor that the scientist manipulates to
determine its effect on the dependent variable. It is the presumed cause in the
experiment .
Question 10: A control group in an experiment is:
A. The group that receives the treatment.
B. The group that is not exposed to the independent variable.
C. The group with the most subjects.
D. The group that is observed first.
CORRECT ANSWER: B. The group that is not exposed to the independent variable.
Rationale:A control group provides a baseline for comparison. It is treated exactly like
the experimental group(s) but does not receive the variable being tested, helping to
isolate the effect of that variable .
Question 11: A theory in science is best defined as:
A. A tentative guess.
B. A well-substantiated explanation of a natural phenomenon.
C. A simple statement of fact.
D. An educated guess.
, CORRECT ANSWER: B. A well-substantiated explanation of a natural phenomenon.
Rationale:A scientific theory is a broad, well-supported explanation that integrates a
large body of evidence. It is not a guess but a robust framework for understanding the
natural world .
Question 12: Which of the following is an example of a physical model?
A. A globe of the Earth
B. A food web diagram
C. The formula for density (D = m/v)
D. A weather map
CORRECT ANSWER: A. A globe of the Earth
Rationale:A physical model is a tangible, three-dimensional representation of an object
or system. A globe is a scaled-down physical model of the Earth .
Question 13: The SI base unit for length is:
A. Foot
B. Yard
C. Meter
D. Kilometer
CORRECT ANSWER: C. Meter
Rationale:The meter is the standard unit of length in the International System of Units
(SI). A kilometer is a derived unit equal to 1000 meters .
Question 14: The metric prefix "milli" means:
A. 1/100
B. 1000
C. 1/1000
D. 100
CORRECT ANSWER: C. 1/1000
Rationale:The prefix "milli" indicates a factor of one-thousandth (10⁻³). For example, 1
milliliter is equal to 1/1000 of a liter .
Question 15: Which of the following is an example of a quantitative observation?
A. The liquid is blue.
B. The rock feels rough.
C. The temperature is 25°C.
D. The solution smells sweet.
CORRECT ANSWER: C. The temperature is 25°C.