The independent variable is the one that you can control or manipulate in an experiment, while the dependent variable is the one that is measured or observed in response to changes in the independent variable.
In the given context:
- Depth of cut is the factor that you are changing or manipulating.
- Level of bleeding is the outcome that you are measuring as a result of the change in the depth of the cut.
Therefore, the independent variable is:
a. Depth of cut.