BIO 101 EXAM 1 — NVCC ACTUAL EXAM
100 Real Exam Questions & Correct Detailed Answers with Rationales (Verified Answers) |
Already Graded
Northern Virginia Community College · General Biology I · Aligned with NVCC BIO 101 Course
Objectives
Cognitive levels: 35% recall · 45% application · 20% analysis · Question style: 70% scenario-based, 30%
direct recall
Domain tags identify the biology concept area for each question (e.g., Scientific Method, Atomic
Structure, pH, Macromolecules, Cell Theory, Organelles, Membrane Transport, Cell Junctions).
SECTION 1 — Scientific Method, Experimental Design, and Data Analysis
(Hypothesis, Variables, Controls, & Graphing)
Q1: [Scientific Method] A researcher observes that plants near a window grow toward the
light. Which step of the scientific method does this represent?
A. Hypothesis
B. Experiment
C. Observation [CORRECT]
D. Conclusion
Correct Answer: C
Rationale: Observation is the first step of the scientific method — gathering information through
the senses or measurements. A hypothesis is a testable explanation; an experiment tests the
hypothesis; a conclusion interprets the results. The scenario describes noticing a natural
phenomenon before any hypothesis is formed.
Q2: [Hypothesis] Which of the following is a properly formulated scientific hypothesis?
A. Plants grow better when they are happy.
B. If plants receive 12 hours of light daily, then they will grow taller than plants receiving
6 hours of light daily. [CORRECT]
C. Light is good for plants.
D. Why do plants grow toward light?
Correct Answer: B
Rationale: A scientific hypothesis must be testable and falsifiable, typically framed as an 'If...
then...' prediction that can be supported or refuted by experiment. The correct option predicts a
measurable outcome (height) based on a manipulated variable (light duration). The other options
are subjective, vague, or are simply questions, not hypotheses.
,Q3: [Variables] An experiment tests the effect of fertilizer concentration on plant height.
Which is the independent variable?
A. Plant height
B. Fertilizer concentration [CORRECT]
C. Type of plant
D. Amount of water
Correct Answer: B
Rationale: The independent variable is the factor the researcher deliberately manipulates — here,
fertilizer concentration. Plant height is the dependent variable (measured outcome); type of plant
and amount of water should be controlled variables held constant to avoid confounding results.
Q4: [Variables] In the same fertilizer experiment, plant height is measured weekly. Plant
height is the:
A. Independent variable
B. Dependent variable [CORRECT]
C. Control variable
D. Constant
Correct Answer: B
Rationale: The dependent variable is the measured outcome that responds to changes in the
independent variable. Plant height is what changes in response to fertilizer concentration, so it is
the dependent variable. NVCC rationale: dependent = data you collect.
Q5: [Control Group] Why is a control group essential in experimental design?
A. To increase sample size
B. To provide a baseline for comparison by holding all variables constant except the
independent variable [CORRECT]
C. To make the experiment faster
D. To prove the hypothesis is correct
Correct Answer: B
Rationale: A control group is held under standard conditions without manipulation of the
independent variable, providing a baseline against which the experimental group's results are
compared. This isolates the effect of the independent variable. Without a control, observed effects
cannot be attributed to the treatment.
Q6: [Sample Size] Why do scientists use large sample sizes in experiments?
A. To make results more statistically reliable and reduce the effect of random variation
[CORRECT]
B. To make the experiment cheaper
C. To avoid needing a control group
D. To prove the hypothesis without statistics
Correct Answer: A
Rationale: Large sample sizes reduce the impact of random variation and individual differences,
increasing statistical reliability. Larger samples also allow valid use of inferential statistics (mean,
standard deviation, p-values). Small samples are vulnerable to outliers and confounders.
, Q7: [Statistics] A data set of plant heights (cm) is: 10, 12, 12, 14, 15, 15, 15, 18. What is the
mode?
A. 12
B. 14
C. 15 [CORRECT]
D. 13.9
Correct Answer: C
Rationale: Mode is the value appearing most frequently. The value 15 appears three times, more
than any other value. Mean = 13.875; median (average of 4th and 5th values) = 14.5. Mode = 15 — the
most common data point.
Q8: [Statistics] For the same data set (10, 12, 12, 14, 15, 15, 15, 18), what is the median?
A. 12
B. 14
C. 14.5 [CORRECT]
D. 15
Correct Answer: C
Rationale: Median is the middle value of an ordered data set. With 8 values (even), median =
average of the 4th and 5th values = (14 + 15)/2 = 14.5. Median is less affected by outliers than mean.
Q9: [Standard Deviation] What does standard deviation measure in a data set?
A. The average value of the data
B. The spread or variability of data around the mean [CORRECT]
C. The most common value
D. The total range of the data
Correct Answer: B
Rationale: Standard deviation measures how widely data points are dispersed around the mean. A
small SD indicates data clustered tightly around the mean; a large SD indicates wide spread. NVCC
rationale: SD quantifies variability, complementing the mean.
Q10: [Graphing] A scientist plots plant height (y-axis) against fertilizer concentration
(x-axis). This type of graph is best described as a:
A. Pie chart
B. Bar graph
C. Line graph (scatter plot with trend) [CORRECT]
D. Histogram
Correct Answer: C
Rationale: A line graph (or scatter plot with trend line) is best for showing the relationship
between two continuous variables — here, plant height vs. fertilizer concentration. Pie charts
show proportions of a whole; bar graphs compare discrete categories; histograms show frequency
distributions of one variable.
100 Real Exam Questions & Correct Detailed Answers with Rationales (Verified Answers) |
Already Graded
Northern Virginia Community College · General Biology I · Aligned with NVCC BIO 101 Course
Objectives
Cognitive levels: 35% recall · 45% application · 20% analysis · Question style: 70% scenario-based, 30%
direct recall
Domain tags identify the biology concept area for each question (e.g., Scientific Method, Atomic
Structure, pH, Macromolecules, Cell Theory, Organelles, Membrane Transport, Cell Junctions).
SECTION 1 — Scientific Method, Experimental Design, and Data Analysis
(Hypothesis, Variables, Controls, & Graphing)
Q1: [Scientific Method] A researcher observes that plants near a window grow toward the
light. Which step of the scientific method does this represent?
A. Hypothesis
B. Experiment
C. Observation [CORRECT]
D. Conclusion
Correct Answer: C
Rationale: Observation is the first step of the scientific method — gathering information through
the senses or measurements. A hypothesis is a testable explanation; an experiment tests the
hypothesis; a conclusion interprets the results. The scenario describes noticing a natural
phenomenon before any hypothesis is formed.
Q2: [Hypothesis] Which of the following is a properly formulated scientific hypothesis?
A. Plants grow better when they are happy.
B. If plants receive 12 hours of light daily, then they will grow taller than plants receiving
6 hours of light daily. [CORRECT]
C. Light is good for plants.
D. Why do plants grow toward light?
Correct Answer: B
Rationale: A scientific hypothesis must be testable and falsifiable, typically framed as an 'If...
then...' prediction that can be supported or refuted by experiment. The correct option predicts a
measurable outcome (height) based on a manipulated variable (light duration). The other options
are subjective, vague, or are simply questions, not hypotheses.
,Q3: [Variables] An experiment tests the effect of fertilizer concentration on plant height.
Which is the independent variable?
A. Plant height
B. Fertilizer concentration [CORRECT]
C. Type of plant
D. Amount of water
Correct Answer: B
Rationale: The independent variable is the factor the researcher deliberately manipulates — here,
fertilizer concentration. Plant height is the dependent variable (measured outcome); type of plant
and amount of water should be controlled variables held constant to avoid confounding results.
Q4: [Variables] In the same fertilizer experiment, plant height is measured weekly. Plant
height is the:
A. Independent variable
B. Dependent variable [CORRECT]
C. Control variable
D. Constant
Correct Answer: B
Rationale: The dependent variable is the measured outcome that responds to changes in the
independent variable. Plant height is what changes in response to fertilizer concentration, so it is
the dependent variable. NVCC rationale: dependent = data you collect.
Q5: [Control Group] Why is a control group essential in experimental design?
A. To increase sample size
B. To provide a baseline for comparison by holding all variables constant except the
independent variable [CORRECT]
C. To make the experiment faster
D. To prove the hypothesis is correct
Correct Answer: B
Rationale: A control group is held under standard conditions without manipulation of the
independent variable, providing a baseline against which the experimental group's results are
compared. This isolates the effect of the independent variable. Without a control, observed effects
cannot be attributed to the treatment.
Q6: [Sample Size] Why do scientists use large sample sizes in experiments?
A. To make results more statistically reliable and reduce the effect of random variation
[CORRECT]
B. To make the experiment cheaper
C. To avoid needing a control group
D. To prove the hypothesis without statistics
Correct Answer: A
Rationale: Large sample sizes reduce the impact of random variation and individual differences,
increasing statistical reliability. Larger samples also allow valid use of inferential statistics (mean,
standard deviation, p-values). Small samples are vulnerable to outliers and confounders.
, Q7: [Statistics] A data set of plant heights (cm) is: 10, 12, 12, 14, 15, 15, 15, 18. What is the
mode?
A. 12
B. 14
C. 15 [CORRECT]
D. 13.9
Correct Answer: C
Rationale: Mode is the value appearing most frequently. The value 15 appears three times, more
than any other value. Mean = 13.875; median (average of 4th and 5th values) = 14.5. Mode = 15 — the
most common data point.
Q8: [Statistics] For the same data set (10, 12, 12, 14, 15, 15, 15, 18), what is the median?
A. 12
B. 14
C. 14.5 [CORRECT]
D. 15
Correct Answer: C
Rationale: Median is the middle value of an ordered data set. With 8 values (even), median =
average of the 4th and 5th values = (14 + 15)/2 = 14.5. Median is less affected by outliers than mean.
Q9: [Standard Deviation] What does standard deviation measure in a data set?
A. The average value of the data
B. The spread or variability of data around the mean [CORRECT]
C. The most common value
D. The total range of the data
Correct Answer: B
Rationale: Standard deviation measures how widely data points are dispersed around the mean. A
small SD indicates data clustered tightly around the mean; a large SD indicates wide spread. NVCC
rationale: SD quantifies variability, complementing the mean.
Q10: [Graphing] A scientist plots plant height (y-axis) against fertilizer concentration
(x-axis). This type of graph is best described as a:
A. Pie chart
B. Bar graph
C. Line graph (scatter plot with trend) [CORRECT]
D. Histogram
Correct Answer: C
Rationale: A line graph (or scatter plot with trend line) is best for showing the relationship
between two continuous variables — here, plant height vs. fertilizer concentration. Pie charts
show proportions of a whole; bar graphs compare discrete categories; histograms show frequency
distributions of one variable.
