In an experimental study of the extent to which mental alertness is inhibited by sleep deprivation,alertness would be the

A) control condition.
B) independent variable.
C) experimental condition.
D) dependent variable.

In this experimental study, the researchers are trying to measure the effect of sleep deprivation on mental alertness, so mental alertness would be the dependent variable. The independent variable is the amount of sleep deprivation that the participants receive. The experimental condition would be the group of participants who are sleep deprived, while the control condition would be the group of participants who have not been sleep deprived. Therefore, the best answer is D, as mental alertness is the dependent variable being measured.