Here's why:

* Independent Variable: The factor that is being manipulated or changed by the experimenter.

* Dependent Variable: The factor that is being measured or observed in response to the change in the independent variable.

In this experiment, you are likely comparing fruits of different densities to see if there is a relationship with healthiness. You are directly controlling the density of the fruit (the independent variable), and then measuring some aspect of healthiness (the dependent variable).

Example:

You could compare the following:

* Independent Variable: Density of apples (low density vs. high density)

* Dependent Variable: Vitamin C content, antioxidant levels, or some other measure of healthiness.

By changing the density of the apples, you are looking to see if there is a change in their healthiness.