Final answer:
The part of the experiment used for ensuring that results are due to the tested variable and not other factors is the control, which is a comparison baseline not subjected to the experimental manipulation.
Step-by-step explanation:
The part of the experiment that acts as a comparison to ensure results are attributed to the variable being tested rather than to other factors is called the control. The control group serves as the baseline in an experiment and is not exposed to the experimental manipulation, which means it does not receive the treatment that the experimental group receives.
This is critical because any changes observed in the experimental group can then be directly associated with the manipulation of the independent variable, which is the variable being tested, as opposed to any other variables present in the experiment. The use of a control group helps to isolate the effect of the independent variable on the dependent variable, ensuring that the research findings are valid and reliable.