Questions: Which is not a step of the scientific method?

The answer is the first one: changing multiple variables in the same trial.

Explanation for each option:

1. Changing multiple variables in the same trial: This is not a step of the scientific method. In a well-designed experiment, only one variable should be changed at a time while keeping other variables constant to ensure that the results are due to the change in the independent variable.

2. Repeating the experiment: This is a step of the scientific method. Repeating experiments helps to verify results and ensure that they are consistent and reliable.

3. Making a specific and measurable prediction about the outcome: This is a step of the scientific method. Formulating a hypothesis involves making a specific and measurable prediction that can be tested through experimentation.

4. Determining reasonable constants, controls, and variables: This is a step of the scientific method. Identifying and maintaining constants and controls, as well as defining variables, is crucial for designing a valid experiment.

Summary: The step that is not part of the scientific method is changing multiple variables in the same trial.