The two sources of energy are the Sun and Earth's interior.
Work Step by Step
The Sun drives external processes that occur in the atmosphere, on the Earth's surface, and in the Hydrosphere. Occurrences such as climate and weather are all driven by the energy of the Sun. For the Earth's interior, heat that has remained in the planet since the time it has formed, is continuously generated by radioactive decay power, which produces earthquakes, forms mountains, and forms volcanoes.