1. which of the following is an example of a controlled experiment? an experiment where there are no…

Brief Explanations:

In a controlled experiment, all variables except the independent variable are kept constant. This means there is only one variable that is being manipulated or changed to observe its effect on the dependent variable. An experiment with no variables is not really an experiment as there is nothing to test. An experiment with many uncontrolled variables cannot accurately determine the cause - and - effect relationship.

Answer:

An experiment where there is only one variable.