Question

in a controlled scientific experiment,
oa. all variables are kept constant.
b. only one variable can be kept constant.
oc. one or more variables are kept constant.
od. no variables are kept constant.

Explanation:

In a controlled scientific experiment, to isolate the effect of the independent variable, one or more factors (variables) that could affect the outcome are held constant. This allows researchers to determine if changes in the dependent variable are due to the manipulation of the independent variable.

Answer:

C. one or more variables are kept constant