Answer: B. Variable
Explanation:
A variable can be define as the characteristic, quantity or number that can be increased or decreased in an experiment, over time or may take different values in different situations.
In an experimental setup two variables are important they are named as independent variable and dependent variable. The independent variable is the variable which can be manipulated in the experiment the affect of which can be observed on the changes that occur on the dependent variable. The dependent variable can take different values in response to the changes in the independent variables.
Control groups can be define as the variable in the experimental setup which does not experience any change. It is kept as a benchmark or standard in the experiment for the comparison of changes occurring in other experimental variables.
On the basis of the above description, In a controlled experiment, variable is the term used to describe the many factors that might be different between the experimental and control groups.
