What is a characteristic of an independent variable in an experiment?

In an experiment, the independent variable is the factor that the researcher deliberately manipulates to observe its effects on other variables, specifically the dependent variable. This characteristic is crucial because it allows scientists to establish cause-and-effect relationships. By altering the independent variable, researchers can measure the outcomes and determine how changes to this variable influence the dependent variable.

For example, if a scientist is studying the effect of fertilizer on plant growth, the amount of fertilizer would be the independent variable. By changing this amount, the scientist can observe how it affects the plants' growth rates. The ability to control and vary the independent variable makes it a fundamental aspect of experimental design.