Final answer:
The dependent variable in the experiment shown is the mass of the plant. The scientists change the amount of fertilizer to observe how it affects the mass of the plants.
Step-by-step explanation:
In the experiment shown, the dependent variable is the mass of the plant. The dependent variable is the factor that is being measured or observed in response to the independent variable, which in this case could be the amount of fertilizer. The scientists would change the amount of fertilizer given to different plants and observe how it affects the mass of the plants. Other factors that might affect plant growth, such as the amount of water, the amount of soil, and the amount of sunshine, should be controlled in the experiment.