If the early atmosphere of the earth was composed of carbon dioxide, why does the present atmosphere contain oxygen molecules?

Select the correct answer. why are scientific models important in the study of science? a. they always involve critical mathematical calculations. b. they scientists understand complex ideas and objects that aren’t easy to handle. c. they enable scientists to popularize their work in society. d. they are required when conducting any peer review process. e. they are necessary for turning a hypothesis into a law.