<span>Answer : D. The factor
that's changed by the experimenter and impacts the dependent variable.<span>
</span><span>An
independent variable is a variable in which you can manipulate or control while
the dependent variable depends on the independent variable. An
example of an independent variable is the running while the dependent variable
is your pulse rate. The pulse rate depends on how fast and how long is the
distance of your run. The pulse rate maybe higher and faster if you’ve run quite
long and will be close to stable if you only run for a short distance and slow
speed.</span></span>
