I'm not so sure if this is correct, but I'm going with king.
The correct answer is any substance or environmental factor other than a steroid
The independent variable is the factor or behavior that is manipulated by the experimenter in order to observe the effect of that manipulation on another factor or behavior that is the dependent variable. To you It is also called the experimental or active variable.
Answer:
Under the studio system of <em>the Golden Age of classic Hollywood.</em>
Explanation:
<em>The studio system (which was used during a period known as the Golden Age of Hollywood) is a method of film production and distribution dominated by a small number of "major" studios in Hollywood.</em>
B. separated twins tend to have the small behavioural characteristic, regardless of the environment.