A controlled variable is the one that is kept constant, the manipulated variable is the independent variable in an experiment , it is called manipulated because is the one that can be changed. A responding variable or variables are the dependent variables that change as a result of the changes in the manipulated variable.
Answer:
sodium
Explanation:
everybody already known its sodium
This is a double replacement because both Copper and Sodium reacted with each other compounds , hence "double"
Respiration. That is the process.
