There are potential variables that are kept constant for each trial in a set of trials.
Your question isn't valid because you need an experimental procedure in place before you determine the variables.
A control sample is the experiment under regular conditions. An experimental sample is the experiment in which different variables are changed.
the experimental variable is like the independent variable, which is the only thing you can change in a science experiment, and the dependent variables are the things that stay the same.
These "variables" are called independent variables or constant variables meaning that they are capable of being changed by the experimenter but are intentionally held the same through each individual experiment.
Variables
There are three types of variables tested: manipulated variables, controlled variables, and experimental variables.
Experimental variables are factors being tested or measured in a scientific experiment. They can be categorized as independent variables (manipulated by the experimenter), dependent variables (respond to the changes in the independent variable), and controlled variables (kept constant to prevent interference).
experimental group or set ups with same variables. OMG i hate scince
things that you change every trial
Independent variable
experimental control
Experimental research involves manipulating variables to observe the effects on an outcome, while non-experimental research does not involve manipulating variables. Experimental research allows researchers to establish cause-and-effect relationships, whereas non-experimental research focuses on observing and describing relationships between variables without manipulation.
the control for multiple variables in a experiment
All variables except one, the experimental variable, are kept constant in an experiment.
Control variables are kept constant throughout an experiment to ensure that any changes in the dependent variable are due to the manipulation of the independent variable. Experimental variables, on the other hand, are the factors that are deliberately changed by the researcher to observe their effect on the dependent variable.
controls for multiple variables in an experiment.