Question

in a controlled experiment, ______. the effects of all of the variables are controlled except the one whose effect the scientist is testing the effects of all of the variables are controlled the scientist controls the experiment a scientist controls the results of the experiment

Explanation:

A controlled experiment isolates the effect of a single independent variable by controlling all other variables, allowing the scientist to observe its specific impact. The other options are incorrect because controlling all variables (no variable tested) or vague "control" without isolation does not define a controlled experiment, and controlling results is unethical/false.

Answer:

the effects of all of the variables are controlled except the one whose effect the scientist is testing