Base your answers only on the contents of the passage. In the case of the Science Reasoning Test, external knowledge has the potential to hurt you. All of the information you need to know is in the passage. You may know more about a subject than the ACT writer designing the questions. If you read something into a question that the ACT writer didn’t intend, you have a good chance of getting the wrong answer.

If you use information that isn’t on the test, you may be outwitting yourself.