Which variable is deliberately changed by the researcher in an experiment?

• A. Dependent variable.
• B. Control variable.
• C. Independent variable.
• D. Constant variable.

Answer: (C)

In an experiment, you change one factor on purpose to see what effect it has. That factor is the independent variable. It’s the element you deliberately tweak to observe how the outcome changes. The thing you measure as the result is the dependent variable. To make the test fair, you keep other factors the same as control variables. There isn’t a standard term “constant variable” in this context—things kept constant are simply control variables. So the reason this option is correct is because the independent variable is the one you deliberately alter to explore cause and effect, while the dependent variable is what you record, and controls are kept constant to avoid other influences.