A biology student wanted to study the effect of fertilizer on the growth of tomato plants. He obtained 40 of the same type of tomato plant and placed them into separate containers, each containing the same amount of soil. Each group (10 plants) received a different watering solution, containing varying amounts of fertilizer. The table below shows the average height of the plants by the end of one week.

Plant group Fertilizer amount (g) Average height of plants (cm)

1 0 3.0

2 5 3.2

3 10 4.4

4 20 5.0

1.Propose an observation that might be the impetus for this experiment.

2.What key question can you ask about the observation proposed in question 1 (1 pt.)?

3.Propose a hypothesis for the experiment. (1 pt.)

4.Which group serves as the control? (1 pt.)

5.Identify the independent variable of this experiment. (1 pt.)
The amount of fertilizer

6.Identify the dependent variable of this experiment. (1 pt.)
The height of the plants

List two controlled variables that should be in the experimental design. (2 pts.)

7.

8.

9. What conclusion can be drawn from this experiment? (1 pt.)

10. Do you think that the further addition of fertilizer will continue to result in improved growth? Propose another experiment that would help support your answer. (2 pts.)