WGU D850 GENERAL BIOLOGY I LAB (BIOL 1011)
PERFORMANCE ASSESSMENT – ORIGINAL
PRACTICE QUESTIONS AND ANSWERS |
2026/2027 LATEST UPDATE
SECTION 1: Scientific Method, Biological Questions, and Hypothesis-Driven Investigation
Questions 1–20
1. Which characteristic best distinguishes a scientific hypothesis from a general
prediction?
A) It is always supported by previously collected data.
B) It provides a testable and potentially falsifiable explanation for an observation.
C) It guarantees the outcome of an experiment.
D) It summarizes the results after an experiment has been completed.
Correct Answer: It provides a testable and potentially falsifiable explanation for an
observation.
Rationale: A scientific hypothesis is a proposed explanation that can be tested through
observation or experimentation. It must be possible for evidence to support or contradict the
explanation. A prediction describes an expected outcome based on a hypothesis, whereas a
conclusion is developed after analyzing experimental evidence.
2. A biologist notices that plants placed near a window appear taller than plants kept
farther from the window. What is the most appropriate initial scientific question?
A) Why do all plants need sunlight?
B) Are plants always taller near windows?
C) Does the amount of light received affect plant growth?
D) Do plants have chloroplasts?
Correct Answer: Does the amount of light received affect plant growth?
Rationale: A useful scientific question identifies variables that can be investigated
experimentally. Here, light exposure can be manipulated or measured while plant growth can
be quantified. The other choices are either too broad, unrelated to the observation, or do not
directly establish a testable relationship between the observed variables.
, 3. What is the primary purpose of a controlled experiment?
A) To eliminate every possible source of biological variation.
B) To guarantee that the hypothesis will be supported.
C) To collect only qualitative observations.
D) To isolate the effect of a selected independent variable while controlling other relevant
factors.
Correct Answer: To isolate the effect of a selected independent variable while controlling
other relevant factors.
Rationale: Controlled experiments are designed so that changes in the dependent variable
can be interpreted in relation to the independent variable. Researchers attempt to hold other
relevant conditions constant. Biological variation cannot always be eliminated, and an
experiment should not be designed to guarantee support for a hypothesis.
4. Which statement represents the strongest scientific hypothesis for an experiment
examining fertilizer and plant growth?
A) Increasing nitrogen fertilizer concentration will increase average plant height over
four weeks, assuming other growing conditions remain constant.
B) Fertilizer is good for plants.
C) Plants need nutrients.
D) Fertilizer probably affects plants somehow.
Correct Answer: Increasing nitrogen fertilizer concentration will increase average plant
height over four weeks, assuming other growing conditions remain constant.
Rationale: A strong hypothesis identifies a measurable independent variable, a measurable
dependent variable, and relevant conditions. The proposed statement can be tested by
manipulating nitrogen concentration and measuring plant height. The other choices are
general statements that do not provide sufficiently specific predictions for a controlled
investigation.
5. What role does an observation play in the scientific method?
A) It automatically proves a hypothesis.
B) It provides information that can lead to a scientific question.
C) It replaces experimental evidence.
D) It is written only after conclusions are reached.
Correct Answer: It provides information that can lead to a scientific question.
,Rationale: Scientific investigations often begin with observations of patterns, events, or
phenomena. Observations can stimulate questions that are subsequently investigated
through hypothesis development and testing. An observation does not automatically
establish causation or prove a hypothesis, and observations can occur throughout an
investigation.
6. Why is falsifiability important when developing a scientific hypothesis?
A) It ensures that every experiment produces statistically significant results.
B) It guarantees reproducibility.
C) It allows evidence to potentially demonstrate that the proposed explanation is incorrect.
D) It prevents researchers from modifying procedures.
Correct Answer: It allows evidence to potentially demonstrate that the proposed
explanation is incorrect.
Rationale: A scientific hypothesis must make claims that can be evaluated against evidence.
Falsifiability means that some possible observation or experimental outcome could
contradict the hypothesis. This characteristic distinguishes scientifically testable explanations
from claims that cannot be evaluated empirically.
7. A researcher predicts that bean plants receiving more hours of light will have greater
average biomass after 30 days. Which variable is the dependent variable?
A) Plant biomass after 30 days.
B) Number of hours of light.
C) Type of bean seed.
D) Duration of the experiment.
Correct Answer: Plant biomass after 30 days.
Rationale: The dependent variable is the outcome measured by the researcher. In this
investigation, biomass is measured to determine whether it changes in response to different
light exposure. Hours of light are manipulated as the independent variable, while other
relevant conditions should be controlled.
8. Which action most directly improves the reproducibility of a biological experiment?
A) Using an unusually complicated procedure.
B) Recording only the final results.
C) Changing procedures whenever unexpected results occur.
D) Documenting the materials, quantities, conditions, and procedures precisely.
, Correct Answer: Documenting the materials, quantities, conditions, and procedures
precisely.
Rationale: Reproducibility requires enough procedural information for another investigator
to repeat the investigation under comparable conditions. Precise documentation reduces
ambiguity and helps identify sources of variation. Altering procedures without
documentation makes replication and interpretation more difficult.
9. Why should a biological investigation include a control when appropriate?
A) The control establishes a comparison against which experimental effects can be
evaluated.
B) The control must always produce the highest value.
C) The control receives every treatment simultaneously.
D) The control eliminates all biological variation.
Correct Answer: The control establishes a comparison against which experimental effects
can be evaluated.
Rationale: A control provides a baseline for interpreting the effect of an experimental
treatment. Comparing treated and control groups helps researchers determine whether
observed differences are associated with the manipulated variable. Controls do not
necessarily produce the highest or lowest measurements and cannot eliminate natural
biological variation.
10. Which statement best describes an independent variable?
A) It is the measurement recorded at the end of an experiment.
B) It is the factor intentionally manipulated or selected for comparison by the researcher.
C) It is always a numerical measurement.
D) It is the conclusion drawn from experimental data.
Correct Answer: It is the factor intentionally manipulated or selected for comparison by
the researcher.
Rationale: The independent variable is the factor whose effect is being investigated. It may
be categorical or quantitative, depending on the experimental design. The dependent
variable is the measured response, while the conclusion is an interpretation developed after
analyzing the collected evidence.
11. What is the primary purpose of replication in an experiment?
A) To make the hypothesis automatically correct.
B) To eliminate the need for controls.
PERFORMANCE ASSESSMENT – ORIGINAL
PRACTICE QUESTIONS AND ANSWERS |
2026/2027 LATEST UPDATE
SECTION 1: Scientific Method, Biological Questions, and Hypothesis-Driven Investigation
Questions 1–20
1. Which characteristic best distinguishes a scientific hypothesis from a general
prediction?
A) It is always supported by previously collected data.
B) It provides a testable and potentially falsifiable explanation for an observation.
C) It guarantees the outcome of an experiment.
D) It summarizes the results after an experiment has been completed.
Correct Answer: It provides a testable and potentially falsifiable explanation for an
observation.
Rationale: A scientific hypothesis is a proposed explanation that can be tested through
observation or experimentation. It must be possible for evidence to support or contradict the
explanation. A prediction describes an expected outcome based on a hypothesis, whereas a
conclusion is developed after analyzing experimental evidence.
2. A biologist notices that plants placed near a window appear taller than plants kept
farther from the window. What is the most appropriate initial scientific question?
A) Why do all plants need sunlight?
B) Are plants always taller near windows?
C) Does the amount of light received affect plant growth?
D) Do plants have chloroplasts?
Correct Answer: Does the amount of light received affect plant growth?
Rationale: A useful scientific question identifies variables that can be investigated
experimentally. Here, light exposure can be manipulated or measured while plant growth can
be quantified. The other choices are either too broad, unrelated to the observation, or do not
directly establish a testable relationship between the observed variables.
, 3. What is the primary purpose of a controlled experiment?
A) To eliminate every possible source of biological variation.
B) To guarantee that the hypothesis will be supported.
C) To collect only qualitative observations.
D) To isolate the effect of a selected independent variable while controlling other relevant
factors.
Correct Answer: To isolate the effect of a selected independent variable while controlling
other relevant factors.
Rationale: Controlled experiments are designed so that changes in the dependent variable
can be interpreted in relation to the independent variable. Researchers attempt to hold other
relevant conditions constant. Biological variation cannot always be eliminated, and an
experiment should not be designed to guarantee support for a hypothesis.
4. Which statement represents the strongest scientific hypothesis for an experiment
examining fertilizer and plant growth?
A) Increasing nitrogen fertilizer concentration will increase average plant height over
four weeks, assuming other growing conditions remain constant.
B) Fertilizer is good for plants.
C) Plants need nutrients.
D) Fertilizer probably affects plants somehow.
Correct Answer: Increasing nitrogen fertilizer concentration will increase average plant
height over four weeks, assuming other growing conditions remain constant.
Rationale: A strong hypothesis identifies a measurable independent variable, a measurable
dependent variable, and relevant conditions. The proposed statement can be tested by
manipulating nitrogen concentration and measuring plant height. The other choices are
general statements that do not provide sufficiently specific predictions for a controlled
investigation.
5. What role does an observation play in the scientific method?
A) It automatically proves a hypothesis.
B) It provides information that can lead to a scientific question.
C) It replaces experimental evidence.
D) It is written only after conclusions are reached.
Correct Answer: It provides information that can lead to a scientific question.
,Rationale: Scientific investigations often begin with observations of patterns, events, or
phenomena. Observations can stimulate questions that are subsequently investigated
through hypothesis development and testing. An observation does not automatically
establish causation or prove a hypothesis, and observations can occur throughout an
investigation.
6. Why is falsifiability important when developing a scientific hypothesis?
A) It ensures that every experiment produces statistically significant results.
B) It guarantees reproducibility.
C) It allows evidence to potentially demonstrate that the proposed explanation is incorrect.
D) It prevents researchers from modifying procedures.
Correct Answer: It allows evidence to potentially demonstrate that the proposed
explanation is incorrect.
Rationale: A scientific hypothesis must make claims that can be evaluated against evidence.
Falsifiability means that some possible observation or experimental outcome could
contradict the hypothesis. This characteristic distinguishes scientifically testable explanations
from claims that cannot be evaluated empirically.
7. A researcher predicts that bean plants receiving more hours of light will have greater
average biomass after 30 days. Which variable is the dependent variable?
A) Plant biomass after 30 days.
B) Number of hours of light.
C) Type of bean seed.
D) Duration of the experiment.
Correct Answer: Plant biomass after 30 days.
Rationale: The dependent variable is the outcome measured by the researcher. In this
investigation, biomass is measured to determine whether it changes in response to different
light exposure. Hours of light are manipulated as the independent variable, while other
relevant conditions should be controlled.
8. Which action most directly improves the reproducibility of a biological experiment?
A) Using an unusually complicated procedure.
B) Recording only the final results.
C) Changing procedures whenever unexpected results occur.
D) Documenting the materials, quantities, conditions, and procedures precisely.
, Correct Answer: Documenting the materials, quantities, conditions, and procedures
precisely.
Rationale: Reproducibility requires enough procedural information for another investigator
to repeat the investigation under comparable conditions. Precise documentation reduces
ambiguity and helps identify sources of variation. Altering procedures without
documentation makes replication and interpretation more difficult.
9. Why should a biological investigation include a control when appropriate?
A) The control establishes a comparison against which experimental effects can be
evaluated.
B) The control must always produce the highest value.
C) The control receives every treatment simultaneously.
D) The control eliminates all biological variation.
Correct Answer: The control establishes a comparison against which experimental effects
can be evaluated.
Rationale: A control provides a baseline for interpreting the effect of an experimental
treatment. Comparing treated and control groups helps researchers determine whether
observed differences are associated with the manipulated variable. Controls do not
necessarily produce the highest or lowest measurements and cannot eliminate natural
biological variation.
10. Which statement best describes an independent variable?
A) It is the measurement recorded at the end of an experiment.
B) It is the factor intentionally manipulated or selected for comparison by the researcher.
C) It is always a numerical measurement.
D) It is the conclusion drawn from experimental data.
Correct Answer: It is the factor intentionally manipulated or selected for comparison by
the researcher.
Rationale: The independent variable is the factor whose effect is being investigated. It may
be categorical or quantitative, depending on the experimental design. The dependent
variable is the measured response, while the conclusion is an interpretation developed after
analyzing the collected evidence.
11. What is the primary purpose of replication in an experiment?
A) To make the hypothesis automatically correct.
B) To eliminate the need for controls.
