BIOLOGY 101: CHAPTERS 1–3 EXAM BANK
LATEST UPDATE 2026|2027|A COMPREHENSIVE
REVIEW OF 300 PRACTICE QUESTIONS WITH
ANSWERS AND RATIONALES |PASS
GUARANTEED
SECTION 1: THE SCIENTIFIC METHOD & EXPERIMENTAL
DESIGN (Questions 1–30)
1. Which of the following is the correct sequence of steps in the scientific method?
A) Hypothesis, Observation, Experiment, Conclusion
B) Observation, Hypothesis, Experiment, Conclusion
C) Experiment, Observation, Hypothesis, Conclusion
D) Observation, Experiment, Hypothesis, Conclusion
Answer: B
Rationale: The scientific method begins with an observation, which leads to a
question and a testable hypothesis. An experiment is then conducted to test the
hypothesis, and finally, a conclusion is drawn. Option A is incorrect because a
hypothesis must be based on an observation. Option C is incorrect because you
cannot experiment before observing and hypothesizing. Option D is incorrect
because a hypothesis must precede the experiment.
2. In a controlled experiment, the group that receives no treatment or a placebo is
called the:
A) Experimental group
B) Independent variable
,C) Control group
D) Dependent variable
Answer: C
Rationale: The control group serves as a baseline for comparison and does not
receive the experimental treatment. Option A is incorrect because the experimental
group receives the treatment. Option B is incorrect because the independent
variable is the factor being manipulated. Option D is incorrect because the
dependent variable is what is being measured.
3. A well-tested explanation for a broad range of observations that is widely
accepted by the scientific community is called a:
A) Hypothesis
B) Theory
C) Law
D) Fact
Answer: B
Rationale: A scientific theory is a broad, well-tested explanation supported by a
large body of evidence. Option A is incorrect because a hypothesis is a tentative,
testable explanation. Option C is incorrect because a law describes a pattern in
nature but does not explain it. Option D is incorrect because a fact is a single
confirmed observation.
4. Which of the following is NOT a characteristic of all living organisms?
A) The ability to reproduce
B) The ability to evolve
C) The ability to photosynthesize
D) The ability to maintain homeostasis
Answer: C
Rationale: Photosynthesis is a characteristic of plants, algae, and some bacteria,
but not all living organisms (e.g., animals, fungi). Options A, B, and D are
,universal characteristics of life: reproduction, evolution, and homeostasis are
shared by all living things.
5. The domain of life that includes organisms with cells that have a true nucleus is:
A) Bacteria
B) Archaea
C) Eukarya
D) Prakarsa
Answer: C
Rationale: Eukarya includes all organisms whose cells contain a membrane-bound
nucleus. Options A and B are incorrect because Bacteria and Archaea are
prokaryotic (lack a true nucleus). Option D is incorrect because "Prokarya" is not a
recognized domain.
6. A scientist observes that a certain drug lowers blood pressure in patients. She
then designs a study to test whether the drug also reduces heart rate. This is an
example of:
A) Forming a hypothesis
B) Making an observation
C) Drawing a conclusion
D) Publishing a theory
Answer: A
Rationale: The scientist is proposing a testable prediction (that the drug reduces
heart rate), which is a hypothesis. Option B is incorrect because an observation has
already been made. Option C is incorrect because no data have been collected yet.
Option D is incorrect because a theory requires extensive testing.
7. In an experiment, the independent variable is:
A) The variable that is measured
B) The variable that is manipulated by the researcher
, C) The variable that remains constant
D) The variable that is unpredictable
Answer: B
Rationale: The independent variable is the factor that the researcher deliberately
changes or manipulates. Option A is incorrect because the measured variable is the
dependent variable. Option C is incorrect because constant variables are controlled
variables. Option D is incorrect because the independent variable is intentionally
set by the researcher.
8. A student wants to test the effect of fertilizer on plant growth. She grows 10
plants with fertilizer and 10 plants without fertilizer. The height of the plants is
measured after 4 weeks. What is the dependent variable?
A) The amount of fertilizer
B) The type of plant
C) The height of the plants
D) The amount of water
Answer: C
Rationale: The dependent variable is what is being measured in response to the
independent variable. Here, plant height is measured. Option A is incorrect because
fertilizer is the independent variable. Options B and D are incorrect because these
are controlled variables.
9. Which of the following best describes a scientific hypothesis?
A) A proven fact
B) A testable prediction
C) A final conclusion
D) A widely accepted theory
Answer: B
Rationale: A hypothesis is a testable prediction or explanation that can be
supported or refuted by experimentation. Option A is incorrect because hypotheses
are not proven facts. Option C is incorrect because a conclusion comes after
LATEST UPDATE 2026|2027|A COMPREHENSIVE
REVIEW OF 300 PRACTICE QUESTIONS WITH
ANSWERS AND RATIONALES |PASS
GUARANTEED
SECTION 1: THE SCIENTIFIC METHOD & EXPERIMENTAL
DESIGN (Questions 1–30)
1. Which of the following is the correct sequence of steps in the scientific method?
A) Hypothesis, Observation, Experiment, Conclusion
B) Observation, Hypothesis, Experiment, Conclusion
C) Experiment, Observation, Hypothesis, Conclusion
D) Observation, Experiment, Hypothesis, Conclusion
Answer: B
Rationale: The scientific method begins with an observation, which leads to a
question and a testable hypothesis. An experiment is then conducted to test the
hypothesis, and finally, a conclusion is drawn. Option A is incorrect because a
hypothesis must be based on an observation. Option C is incorrect because you
cannot experiment before observing and hypothesizing. Option D is incorrect
because a hypothesis must precede the experiment.
2. In a controlled experiment, the group that receives no treatment or a placebo is
called the:
A) Experimental group
B) Independent variable
,C) Control group
D) Dependent variable
Answer: C
Rationale: The control group serves as a baseline for comparison and does not
receive the experimental treatment. Option A is incorrect because the experimental
group receives the treatment. Option B is incorrect because the independent
variable is the factor being manipulated. Option D is incorrect because the
dependent variable is what is being measured.
3. A well-tested explanation for a broad range of observations that is widely
accepted by the scientific community is called a:
A) Hypothesis
B) Theory
C) Law
D) Fact
Answer: B
Rationale: A scientific theory is a broad, well-tested explanation supported by a
large body of evidence. Option A is incorrect because a hypothesis is a tentative,
testable explanation. Option C is incorrect because a law describes a pattern in
nature but does not explain it. Option D is incorrect because a fact is a single
confirmed observation.
4. Which of the following is NOT a characteristic of all living organisms?
A) The ability to reproduce
B) The ability to evolve
C) The ability to photosynthesize
D) The ability to maintain homeostasis
Answer: C
Rationale: Photosynthesis is a characteristic of plants, algae, and some bacteria,
but not all living organisms (e.g., animals, fungi). Options A, B, and D are
,universal characteristics of life: reproduction, evolution, and homeostasis are
shared by all living things.
5. The domain of life that includes organisms with cells that have a true nucleus is:
A) Bacteria
B) Archaea
C) Eukarya
D) Prakarsa
Answer: C
Rationale: Eukarya includes all organisms whose cells contain a membrane-bound
nucleus. Options A and B are incorrect because Bacteria and Archaea are
prokaryotic (lack a true nucleus). Option D is incorrect because "Prokarya" is not a
recognized domain.
6. A scientist observes that a certain drug lowers blood pressure in patients. She
then designs a study to test whether the drug also reduces heart rate. This is an
example of:
A) Forming a hypothesis
B) Making an observation
C) Drawing a conclusion
D) Publishing a theory
Answer: A
Rationale: The scientist is proposing a testable prediction (that the drug reduces
heart rate), which is a hypothesis. Option B is incorrect because an observation has
already been made. Option C is incorrect because no data have been collected yet.
Option D is incorrect because a theory requires extensive testing.
7. In an experiment, the independent variable is:
A) The variable that is measured
B) The variable that is manipulated by the researcher
, C) The variable that remains constant
D) The variable that is unpredictable
Answer: B
Rationale: The independent variable is the factor that the researcher deliberately
changes or manipulates. Option A is incorrect because the measured variable is the
dependent variable. Option C is incorrect because constant variables are controlled
variables. Option D is incorrect because the independent variable is intentionally
set by the researcher.
8. A student wants to test the effect of fertilizer on plant growth. She grows 10
plants with fertilizer and 10 plants without fertilizer. The height of the plants is
measured after 4 weeks. What is the dependent variable?
A) The amount of fertilizer
B) The type of plant
C) The height of the plants
D) The amount of water
Answer: C
Rationale: The dependent variable is what is being measured in response to the
independent variable. Here, plant height is measured. Option A is incorrect because
fertilizer is the independent variable. Options B and D are incorrect because these
are controlled variables.
9. Which of the following best describes a scientific hypothesis?
A) A proven fact
B) A testable prediction
C) A final conclusion
D) A widely accepted theory
Answer: B
Rationale: A hypothesis is a testable prediction or explanation that can be
supported or refuted by experimentation. Option A is incorrect because hypotheses
are not proven facts. Option C is incorrect because a conclusion comes after
