Involves both an experimental group and a control group, which are alike except for the one variable that the experiment is designed to test.

The answer is controlled experiment because it is a way of having both groups such as the experimental and control group and having exception one variable in regards to the designed test. This is a type of experimentation in a way that there is only one variable that is being adjusted which could be referred to as the independent variable while the other variable will only be the one affected of the variable that has been adjusted. The one adjusted is the independent variable and the one that has been affected with the change is the dependent variable. This could portray the experimental group and the control group being done in an experiment.

in the analysis of systems that involve fluid flow, we frequently encounter the combination of properties u and pv.