Describe the organism that scientists believe was responsible for changing the composition of the early atmosphere. what is it called and how did it change the atmosphere? why was this change to the atmosphere so important?

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.