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BIO 103 Exam 1 Actual Exam Questions and
Verified Answers 2026/2027 with Detailed
Rationales Grade A Study Guide
1. A farmer wonders if adding nitrogen-based fertilizer increases fruit yield in all crops.
He adds nitrogen-based fertilizer to a tomato plant and a corn plant on his farm. He
measures the sizes of fruits in both plants and finds that both species have yielded
larger fruits after the application. He proclaims, "Nitrogen-based fertilizer increases
fruit yield in all crops." This is an example of:
A. A scientific law
B. A scientific theory
C. A fact
D. Neither law, theory, nor fact
Correct Answer: D. Neither law, theory, nor fact
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Rationale: The farmer's conclusion is based on insufficient evidence (only two plants)
and lacks proper controls. It does not meet the criteria for a scientific law, theory, or
established fact.
2. Why are theories stronger and more reliable than hypotheses?
A. Theories are based on guesses, while hypotheses are proven
B. Theories are based on many experimentally tested hypotheses
C. Theories cannot be changed, while hypotheses can
D. Theories are older than hypotheses
Correct Answer: B. Theories are based on many experimentally tested hypotheses
Rationale: Theories are comprehensive explanations supported by a vast body of
evidence from many experimentally tested hypotheses, making them more reliable than
individual hypotheses.
3. A farmer adds nitrogen-based fertilizer to two tomato plants and two corn plants on
his farm. He measures the sizes of fruits in both plants and finds that both species
have yielded larger fruits after the application. What was the major problem with the
farmer's experiment?
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A. He used too many plants
B. There was no control group
C. He measured the wrong variable
D. He used only two species
Correct Answer: B. There was no control group
Rationale: The experiment lacked a control group (plants that did not receive fertilizer)
to compare against the treated plants, making it impossible to determine if the fertilizer
caused the growth.
4. Identify the dependent variable in the statement below: "Carbon dioxide is one of
the 'greenhouse gases' which allows the atmosphere to trap heat. Increased
atmospheric carbon dioxide levels will therefore increase atmospheric temperature."
A. Carbon dioxide levels
B. Greenhouse gases
C. Atmospheric temperature
D. Heat trapping ability
Correct Answer: C. Atmospheric temperature
BIO 103 Exam 1 Actual Exam Questions and
Verified Answers 2026/2027 with Detailed
Rationales Grade A Study Guide
1. A farmer wonders if adding nitrogen-based fertilizer increases fruit yield in all crops.
He adds nitrogen-based fertilizer to a tomato plant and a corn plant on his farm. He
measures the sizes of fruits in both plants and finds that both species have yielded
larger fruits after the application. He proclaims, "Nitrogen-based fertilizer increases
fruit yield in all crops." This is an example of:
A. A scientific law
B. A scientific theory
C. A fact
D. Neither law, theory, nor fact
Correct Answer: D. Neither law, theory, nor fact
,2|Page
Rationale: The farmer's conclusion is based on insufficient evidence (only two plants)
and lacks proper controls. It does not meet the criteria for a scientific law, theory, or
established fact.
2. Why are theories stronger and more reliable than hypotheses?
A. Theories are based on guesses, while hypotheses are proven
B. Theories are based on many experimentally tested hypotheses
C. Theories cannot be changed, while hypotheses can
D. Theories are older than hypotheses
Correct Answer: B. Theories are based on many experimentally tested hypotheses
Rationale: Theories are comprehensive explanations supported by a vast body of
evidence from many experimentally tested hypotheses, making them more reliable than
individual hypotheses.
3. A farmer adds nitrogen-based fertilizer to two tomato plants and two corn plants on
his farm. He measures the sizes of fruits in both plants and finds that both species
have yielded larger fruits after the application. What was the major problem with the
farmer's experiment?
, 3|Page
A. He used too many plants
B. There was no control group
C. He measured the wrong variable
D. He used only two species
Correct Answer: B. There was no control group
Rationale: The experiment lacked a control group (plants that did not receive fertilizer)
to compare against the treated plants, making it impossible to determine if the fertilizer
caused the growth.
4. Identify the dependent variable in the statement below: "Carbon dioxide is one of
the 'greenhouse gases' which allows the atmosphere to trap heat. Increased
atmospheric carbon dioxide levels will therefore increase atmospheric temperature."
A. Carbon dioxide levels
B. Greenhouse gases
C. Atmospheric temperature
D. Heat trapping ability
Correct Answer: C. Atmospheric temperature
