# Which is a dependent variable in this experiment?

MULTIPLE CHOICE SECTION INSTRUCTIONS: Read all instructions carefully. Please answer all questions. Each question is worth 1 point. The Multiple Choice section is worth 20 points.

1. What is the correct sequence of steps in the scientific method?

I. Make observations and ask a question

II. Analyze the data

III. Develop a hypothesis

IV. Share the results with other scientists

V. Design and perform an experiment to test the hypothesis

A) I>II > III > IV > V

B) III > I > V > II > IV

C) V> IV > III > II > I

D) I> III > V >II > IV

E) V > II > I > III > IV

2. You have formulated a hypothesis: “Apples contain more vitamin C than oranges.”

To test your hypothesis you measure vitamin C levels in 20 oranges and 20 apples from trees that were grown in the same orchard under the same environmental conditions (temperature, rain, sunlight). This experiment was conducted twice. The control group in the experiment is

A) type of soil, temperature, amount of rain and sunlight in the orchard

B) vitamin C levels

C) oranges

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D) apples

E) a large sample size and repeated experiment

***Use the following information to answer questions 3, 4, 5 & 6 below***:

A group of medical researchers investigated the effects of Drug X on lowering cholesterol levels in a group of men between the ages of 50 and 70 years old. The researchers did the following experiment and obtained the indicated results: One group of 150 men took a tablet containing Drug X for 3 weeks – 95 of these men decreased their cholesterol levels by at least 10% (three men from this group dropped out of the study). Another group of 150 men was given a tablet with no added Drug X for 3 weeks – 10 of these men decreased their cholesterol levels by at least 10% (two men from this group dropped out of the study).

3. Which of the following is the best hypothesis for this experiment?

A) Will drug X lower cholesterol levels in men between the age of 50 and 70 years?

B) Drug X will lower cholesterol levels in men.

C) Since high cholesterol levels significantly increases several health risks for men, drug X is most likely beneficial.

D) Men between the age of 50 and 70 years will have reduced cholesterol levels if they take drug X over a 3 week period.

E) There is no significant difference in cholesterol levels between men that take drug X and those that don’t take it.

4. Which of the following was the control group in this experiment?

A) the amount of Drug X contained in the tablet

B) the number of participants in each group at the end of the experiment

C) the group of participants that received tablets containing Drug X

D) the group of participants that received tablets that did not contain Drug X

E) the number of participants in each group at the beginning of the experiment

5. Which of the following is a dependent variable in this experiment?

A) the amount of Drug X contained in the tablet

B) participants that received tablets containing Drug X

C) the average age of the participants

D) number of participants in each group at the beginning of the experiment

E) cholesterol levels

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6. Which of the following is an independent variable in this experiment?

A) the amount of Drug X contained in the tablet

B) participants that received tablets containing Drug X

C) the average age of the participants

D) number of participants in each group at the beginning of the experiment

E) blood pressure

7. A chemotherapy drug affects the enzyme DNA polymerase. In which part of the cell cycle does it inhibit cell division?

A) Metaphase

B) S phase

C) G1

D) Cytokinesis

E) Prophase

8. A researcher planted seeds from four types of tomatoes (Roma, Cherry, Big Boy and Early Girl) in a greenhouse to determine which type of tomato produce the largest number of tomatoes per plant. The plants were grown for 70 days under the same temperature and light conditions. The average results for 20 plants of each type are shown below. Choose the data set that demonstrates that Cherry tomatoes produce the largest number of tomatoes per plant.

A) Roma: 20 tomatoes, Cherry: 18 tomatoes, Big Boy: 30 tomatoes, Early Girl: 10 tomatoes

B) Roma: 1.8 lbs, Cherry: 2.8 lbs, Big Boy: 2.7 lbs, Early Girl: 1.0 lbs

C) Roma: 3 cm, Cherry: 1 cm, Big Boy: 10 cm, Early Girl: 7 cm

D) Roma: 2 cm, Cherry: 10 cm, Big Boy: 7 cm, Early Girl: 6 cm

E) Roma: 23 tomatoes, Cherry: 28 tomatoes, Big Boy: 10 tomatoes, Early Girl: 27 tomatoes

9. The majority of climate scientists believe that the current change in climate is caused predominantly by ________.

A) an increase of the greenhouse effect

B) a decreased reliance on fossil fuels for energy

C) a thinning of the ozone layer

D) a melting of the polar ice caps

E) an increase in solar radiation

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10. Based on the following phylogenetic tree, which of the following conclusions are *NOT* correct? Each letter represents a hypothetical species.

A) A and E share a common ancestor

B) B is one of A’s ancestors

C) E and D are more closely related to each other than to C

D) C is more closely related to E than to B

E) A and B are closely related