The origin of life on Earth has been the subject of scientific study, and several theories developed to clarify it. A. The Oparin-Haldane hypothesis about the origin of life explained the relationship between early atmosphere and chemical reactions but it has been abandoned by modern scientists. B. All of the hypotheses about the origin of life have been disproved, and it seems impossible to devise better hypotheses. C. Organic compounds can occur and remain stable in interstellar space and these chemicals may have led to the origin of life after they reached Earth. D. One theory assumed that organic molecules formed at hydrothermal vents are responsible for the origin of life, and the high temperatures in some vents make such molecules unstable. E. One theory argues that molecules in the cold interstellar environment reacted in the heat of hydrothermal vents, creating the stable organic molecules which are essential for life. F. Modern hypothesis suggested life may come from chemical reactions in Earth's ocean, but some scientists still doubt that the chemical products would have concentrated or long lasting enough.