All weather that happens in Earth's atmosphere occurs in the troposphere. Choose the best two reasons for this. A) The troposphere is the atmospheric level closest to Earth's surface. B) Of all atmospheric levels, the troposphere contains the most water vapor. C) The troposphere has equal parts of nitrogen and oxygen, which creates clouds. D) The troposphere is the only level of atmosphere that is affected by gravity. E) The Sun's light controls the water cycle, and it only reaches the troposphere