Answer:
Control
Step-by-step explanation:
Experimental control: In research, the term experimental control is defined as a technique used by an experimenter to minimize or decrease the effects of environmental variables and extraneous experience and therefore strengthening the interference that leads to change in the dependent variable because of the presence of the independent variable.
Function: It holds constant particular variables in an experiment for which the researcher is not interested to measure.
In the question above, Roberto has successfully created an experimental control.