2026 WGU C190 Introduction to Biology - Practice Questions |
Complete Objective Assessment (OA) Review Test Bank with
Verified Answers
Pass your Western Governors University Objective Assessment on your
first attempt with this comprehensive C190 Introduction to Biology test bank
featuring practice questions. This targeted preparation guide provides
verified correct answers and clear explanations covering cell structure,
DNA replication, genetics, evolution, and ecosystem dynamics. It is the
ultimate resource for WGU students looking to master essential life science
concepts quickly and secure a passing grade.
Question 1: A researcher observes that a certain species of orchid
produces larger flowers in shaded areas compared to sunny areas. The
researcher hypothesizes that light intensity affects flower size. What is
the independent variable in this experiment?
A) Flower size
B) Light intensity
C) Orchid species
D) Soil type
Answer: B) Light intensity
Rationale: The independent variable is the factor that the researcher
manipulates or changes to observe its effect. In this case, the researcher is
studying how light intensity affects flower size, so light intensity is the
independent variable. Flower size is the dependent variable (the measured
outcome), orchid species and soil type are controlled variables .
,Question 2: Which characteristic of living organisms is best illustrated
by a sunflower turning its head to face the sun throughout the day?
A) Reproduction
B) Growth and development
C) Response to stimuli
D) Energy utilization
Answer: C) Response to stimuli
Rationale: The sunflower's movement in response to light direction is an
example of responding to environmental stimuli. This is a fundamental
characteristic of life. Phototropism allows plants to maximize light absorption
for photosynthesis. Reproduction, growth, and energy utilization are also
characteristics of life but do not describe this specific behavior .
Question 3: A scientist wants to test the effect of caffeine on the heart
rate of water fleas (Daphnia). Which of the following would be the
best control group?
A) Water fleas exposed to 1% caffeine solution
B) Water fleas exposed to distilled water only
C) Water fleas exposed to 5% caffeine solution
D) Water fleas exposed to sugar solution
Answer: B) Water fleas exposed to distilled water only
Rationale: A control group should be identical to the experimental groups
except for the variable being tested. Distilled water without caffeine serves as
a proper control, allowing the scientist to determine if any changes in heart
rate are due to caffeine rather than other factors. The other options introduce
additional variables or different concentrations of caffeine .
,Question 4: Which of the following is an example of a qualitative
observation?
A) The plant grew 15 centimeters in one month
B) The solution has a temperature of 37°C
C) The leaves turned yellow and wilted
D) The fish weighs 200 grams
Answer: C) The leaves turned yellow and wilted
Rationale: Qualitative observations are descriptive and non-numerical,
focusing on qualities, characteristics, or properties. "Yellow and wilted"
describes the condition of the leaves without using numbers. The other
options are quantitative observations that involve numerical measurements .
Question 5: A hypothesis is best described as:
A) An educated guess that has been proven
B) A tentative explanation for an observation that can be tested
C) A fact that is universally accepted
D) The final conclusion of an experiment
Answer: B) A tentative explanation for an observation that can be
tested
Rationale: A hypothesis is a proposed explanation for a phenomenon that is
testable through experimentation or further observation. It is not proven (that
would be a theory), nor is it a fact or final conclusion. Hypotheses are refined
or rejected based on experimental results .
Question 6: Which of the following is NOT a trace element required by
living organisms?
, A) Copper
B) Zinc
C) Carbon
D) Manganese
Answer: C) Carbon
Rationale: Carbon is a major element required in large quantities by living
organisms. It forms the backbone of all organic molecules. Copper, zinc, and
manganese are trace elements that are required in very small amounts (less
than 0.01% of body mass) for essential biological functions .
Question 7: An atom has 8 protons, 8 neutrons, and 8 electrons. What
is its atomic number?
A) 8
B) 16
C) 24
D) 4
Answer: A) 8
Rationale: The atomic number of an atom equals the number of protons in its
nucleus. This atom has 8 protons, so its atomic number is 8. The mass
number is the sum of protons and neutrons (8 + 8 = 16), but the atomic
number is determined solely by the number of protons .
Question 8: Which of the following describes an isotope?
A) Atoms of the same element with different numbers of neutrons
B) Atoms of different elements with the same number of protons
Complete Objective Assessment (OA) Review Test Bank with
Verified Answers
Pass your Western Governors University Objective Assessment on your
first attempt with this comprehensive C190 Introduction to Biology test bank
featuring practice questions. This targeted preparation guide provides
verified correct answers and clear explanations covering cell structure,
DNA replication, genetics, evolution, and ecosystem dynamics. It is the
ultimate resource for WGU students looking to master essential life science
concepts quickly and secure a passing grade.
Question 1: A researcher observes that a certain species of orchid
produces larger flowers in shaded areas compared to sunny areas. The
researcher hypothesizes that light intensity affects flower size. What is
the independent variable in this experiment?
A) Flower size
B) Light intensity
C) Orchid species
D) Soil type
Answer: B) Light intensity
Rationale: The independent variable is the factor that the researcher
manipulates or changes to observe its effect. In this case, the researcher is
studying how light intensity affects flower size, so light intensity is the
independent variable. Flower size is the dependent variable (the measured
outcome), orchid species and soil type are controlled variables .
,Question 2: Which characteristic of living organisms is best illustrated
by a sunflower turning its head to face the sun throughout the day?
A) Reproduction
B) Growth and development
C) Response to stimuli
D) Energy utilization
Answer: C) Response to stimuli
Rationale: The sunflower's movement in response to light direction is an
example of responding to environmental stimuli. This is a fundamental
characteristic of life. Phototropism allows plants to maximize light absorption
for photosynthesis. Reproduction, growth, and energy utilization are also
characteristics of life but do not describe this specific behavior .
Question 3: A scientist wants to test the effect of caffeine on the heart
rate of water fleas (Daphnia). Which of the following would be the
best control group?
A) Water fleas exposed to 1% caffeine solution
B) Water fleas exposed to distilled water only
C) Water fleas exposed to 5% caffeine solution
D) Water fleas exposed to sugar solution
Answer: B) Water fleas exposed to distilled water only
Rationale: A control group should be identical to the experimental groups
except for the variable being tested. Distilled water without caffeine serves as
a proper control, allowing the scientist to determine if any changes in heart
rate are due to caffeine rather than other factors. The other options introduce
additional variables or different concentrations of caffeine .
,Question 4: Which of the following is an example of a qualitative
observation?
A) The plant grew 15 centimeters in one month
B) The solution has a temperature of 37°C
C) The leaves turned yellow and wilted
D) The fish weighs 200 grams
Answer: C) The leaves turned yellow and wilted
Rationale: Qualitative observations are descriptive and non-numerical,
focusing on qualities, characteristics, or properties. "Yellow and wilted"
describes the condition of the leaves without using numbers. The other
options are quantitative observations that involve numerical measurements .
Question 5: A hypothesis is best described as:
A) An educated guess that has been proven
B) A tentative explanation for an observation that can be tested
C) A fact that is universally accepted
D) The final conclusion of an experiment
Answer: B) A tentative explanation for an observation that can be
tested
Rationale: A hypothesis is a proposed explanation for a phenomenon that is
testable through experimentation or further observation. It is not proven (that
would be a theory), nor is it a fact or final conclusion. Hypotheses are refined
or rejected based on experimental results .
Question 6: Which of the following is NOT a trace element required by
living organisms?
, A) Copper
B) Zinc
C) Carbon
D) Manganese
Answer: C) Carbon
Rationale: Carbon is a major element required in large quantities by living
organisms. It forms the backbone of all organic molecules. Copper, zinc, and
manganese are trace elements that are required in very small amounts (less
than 0.01% of body mass) for essential biological functions .
Question 7: An atom has 8 protons, 8 neutrons, and 8 electrons. What
is its atomic number?
A) 8
B) 16
C) 24
D) 4
Answer: A) 8
Rationale: The atomic number of an atom equals the number of protons in its
nucleus. This atom has 8 protons, so its atomic number is 8. The mass
number is the sum of protons and neutrons (8 + 8 = 16), but the atomic
number is determined solely by the number of protons .
Question 8: Which of the following describes an isotope?
A) Atoms of the same element with different numbers of neutrons
B) Atoms of different elements with the same number of protons
