Answer:
A variable, which is monitored or changed while performing an experiment in order to examine the influences on the dependent variable is considered as the independent variable. On the other hand, the variable, which is being determined and examined while performing an experiment is known as a dependent variable.
The dependent variable bank upon the independent variable. As the researcher modifies the independent variable, the influence on the dependent variable is witnessed and noted. In the given case, a soldier is exposed to a stressful environment, which makes a change in his blood pressure.
It is noted that with the change in the environmental condition, a change is noticed in the blood pressure of the soldier. Thus, in the given case, the stressful environment is an independent variable, and the change in blood pressure is a dependent variable.