Tiffany was investing how fast it took Hayden to react to different sounds. Identify the independent variable. A. how fast Hayden reacted
B. different sounds
C. playing the trumpet over and over
D. how much time it took Hayden to react
E. Hayden

Why is it important for scientists to review and repeat the work of other scientists? 1.a scientific theory must be tested three times before it is proven. 2.the scientific method only applies to repeated experiments. 3.an experiment may have had errors that the scientists didn't recognize. 4.the results of individual scientists may be influenced by bias. 5.an experiment must be performed twice before the data can be analyzed.