Emilios teacher told his class that a controlled experiments results are valid only if one factor in the experiment is changed and all the other factors remain constant. why is this statement true?

When only one factor is changed, you can be more certain that it caused the results.

Explanation:

A controlled experiment is usually performed to determine the effect of a certain factor. If more than one factor is changed in a single experiment, then we won't be able o determine which factor was responsible for bringing the change in our experiment. Hence, it is important that in controlled experiments, we study one factor at a time. Study of more than one factor will not give reliable results.

answer; i believe the correct answer is (data); /// good luck