Step-by-step explanation:
In experiments of enzyme catalyzed reactions, the manipulated variable is the variable that is changed by the experimenter. This variable is also known as the independent variable. For example, the concentration of the substrate can be manipulated to observe its effect on the rate of the reaction.
The responding variable is the variable that is measured in response to the changes in the manipulated variable. This variable is also known as the dependent variable. In the case of enzyme catalyzed reactions, the rate of the reaction is the responding variable.
The controlled variable is the variable that is kept constant throughout the experiment. This variable is also known as the constant variable. In the case of enzyme catalyzed reactions, the temperature, pH, and enzyme concentration are some of the controlled variables.
1 provides more information on identifying the manipulated, responding, and controlled variables in experiments of enzyme catalyzed reactions.