what is the independent variable
In an experiment or study, the independent variable is the variable that is changed or manipulated by the researcher to determine its effects on the dependent variable. It's called "independent" because its variation does not depend on other variables within the experiment.
For example, if you are conducting an experiment to see if the amount of sunlight affects the growth rate of a plant, the independent variable would be the amount of sunlight each plant receives. The dependent variable would be the growth rate of the plant, which you'd measure to see how it changes in response to varying amounts of sunlight.
In summary, the independent variable is the presumed cause, while the dependent variable is the presumed effect. The independent variable is what you manipulate to test its effects on the outcome you're observing.