Final answer:
In experimental situations, researchers hold everything constant except for the independent variables, as those are the ones they manipulate to observe effects on dependent variables.
Step-by-step explanation:
Ideally, everything in the experimental situation except the independent variables is held constant. This is because independent variables are the ones that researchers manipulate to observe the effects on the dependent variables, which are the outcomes measured in the experiment. In a controlled experiment, researchers aim to hold all other variables constant so that any observed changes in the dependent variable can be attributed to the manipulation of the independent variable.