Final answer:
Naturalistic observation is not a characteristic of an experiment, which involves manipulation of variables and controlled conditions.
Step-by-step explanation:
One characteristic that is NOT a characteristic of an experiment is c) Naturalistic observation. An experiment involves manipulating an independent variable and observing its effect on a dependent variable. It requires randomization of subjects to minimize bias and controlled variables to isolate the effect of the independent variable. Naturalistic observation, on the other hand, involves observing and recording behavior in a natural setting without any manipulation of variables.