Dr. Jones systematically varies the brightness in the laboratory (400, 800, and 1600 lumens) while holding other variables constant, and observes that the participants’ activity level decreases as the brightness decreases. This illustrates

Cause and effect

Explanation:

In this experiment Dr. Jones is observing the dynamic change in behaviour with the systematic change in brightness. He remains all the variables the same, these are called the dependent variables. The change in lumens is the variable that changes is called the independent variable. Every experiment that is done always have a number of variables to contend with. Scientists will keep all the variable s the same in order to examine the effect that the dynamic variable has on the system. In this experiment Dr Jones is seeking the effect on lumens on behaviour in terms of cause and effect.

answer; i believe that the correct answer is ( rivers);

i think it's the cabinet