Question 1

Which of the following best describes a null hypothesis in a scientific experiment?

Accepted Answer

A statement that the independent variable will have no effect on the dependent variable.

Question 2

A scientist is testing the effect of different concentrations of salt on plant growth. Which variable is the dependent variable in this experiment?

Accepted Answer

The growth (height) of the plant

Question 3

In a controlled experiment, why is it important to keep all variables except the independent variable constant?

Accepted Answer

To ensure that the results are due to the independent variable alone

Question 4

A researcher wants to test whether a new drug reduces blood pressure. She gives the drug to one group and a placebo to another. What is the purpose of the placebo group?

Accepted Answer

To serve as a control group for comparison

Question 5

Which of the following is the correct format for a hypothesis statement?

Accepted Answer

If the independent variable is changed, then the dependent variable will change in a specific way.

Question 6

A student is graphing the results of an experiment measuring the effect of temperature on enzyme activity. Which variable should be placed on the x-axis?

Accepted Answer

Temperature

Question 7

Which of the following best explains why scientific experiments must be repeated multiple times?

Accepted Answer

To ensure the results are consistent and reliable

Question 8

A bar graph is most appropriate for which type of data?

Accepted Answer

Data comparing categories or groups

Question 9

Which of the following is NOT a characteristic of a well-designed controlled experiment?

Accepted Answer

Multiple dependent variables are measured simultaneously

Question 10

A scientist collects data on the effect of pH on bacterial growth. The data is best displayed using which type of graph?

Accepted Answer

Line graph

Question 11

Which of the following statements about scientific conclusions is correct?

Accepted Answer

A conclusion is based on evidence collected from the experiment.

Question 12

In the context of the scientific method, what is the primary purpose of peer review?

Accepted Answer

To ensure the experiment can be replicated and is free from major flaws

Question 13

A student hypothesizes that increasing the amount of sunlight will increase the rate of photosynthesis in plants. Which of the following is the best null hypothesis for this experiment?

Accepted Answer

The amount of sunlight has no effect on the rate of photosynthesis.

Question 14

Which of the following best describes the relationship between the independent and dependent variables in an experiment?

Accepted Answer

The dependent variable changes in response to the independent variable.

Question 15

A scientist is testing the effect of fertilizer on plant growth. She uses three different brands of fertilizer and measures plant height after four weeks. What is the independent variable?

Accepted Answer

The type of fertilizer used

Question 16

Which of the following is an example of a claim in the Claim-Evidence-Reasoning (CER) framework?

Accepted Answer

Plants exposed to more sunlight grew taller than those in the shade.

Question 17

Which of the following best explains why a graph with a misleading scale can be problematic in scientific communication?

Accepted Answer

It can exaggerate or minimize differences in the data, leading to incorrect interpretations.

Question 18

A student is designing an experiment to test the effect of exercise on heart rate. Which of the following is the best way to ensure the results are valid?

Accepted Answer

Keep all variables except the duration of exercise constant.

Question 19

Which of the following is the correct way to write a hypothesis using the variables: temperature (independent) and enzyme activity (dependent)?

Accepted Answer

If the temperature increases, then enzyme activity will increase up to an optimal point and then decrease.

Question 20

A scientist wants to test the effect of a new vaccine. She divides volunteers into two groups: one receives the vaccine, the other receives a placebo. Which of the following is a constant in this experiment?

Accepted Answer

The size, shape, color, and texture of the pill

Nature of Science: Scientific Method, Experimental Design, and Graphing

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