Answer: Independent variable
Step-by-step explanation:
Independent variable can be defined as the variable that can be changed in the experiment. This variable can be changed to see the effect of it on the dependent variable.
In contrast to this is the dependent variable which cannot be changed and is dependent on the independent variable.
So, the factor that can be changed in the experiment is the independent variable. It can be any factor like change in time, change in concentration of time et cetera.