Answer:
An independent variable
Step-by-step explanation:
To understand the concept of independent variables, one should understand the meaning of variable.
Variables is any characteristics, numer, or quantity that can be measured or counted. A variable can also be called a data item. Age, sex, business income and expenditures, country birth, capital expenditure, class grades, eye colour and vehicle type are all examples of variables, they are all called variable because the value may vary between data units in a population and may change in value over time.
Independent variables are variables that are manipulated or are changed by researchers and whose effects are measured and compared. The independent variables are called such because independent variables predict or forecast the value of the dependent variable model.