Final answer:
The level of geological activity on planets and moons is largely determined by their ability to retain internal heat, influenced by their size and the decay of radioactive elements. Additionally, tidal heating due to gravitational interactions with larger planets can enhance geological activity, as seen with moons like Io and Enceladus.
Step-by-step explanation:
The geological activity observed on various planets and moons within our Solar System varies significantly due to several factors. One primary reason is the retention of internal heat, which is more effective in larger planetary bodies as they cool more slowly, much like a large 'baked potato,' often referenced in planetary science. This effect is strongly tied to the presence of primordial heat from the formation of these celestial objects, as well as the heat produced by the decay of radioactive elements within their interiors. Earth and Venus exemplify terrestrial planets with high geological activity due to their greater mass.
Additionally, tidal heating can play a significant role in driving geological activity. Planetary bodies like Jupiter's moon Io or Saturn's moon Enceladus experience considerable geological activity because of the gravitational interaction with their parent planets, which causes internal friction and heat. In contrast, smaller objects like our Moon have cooled significantly and exhibit minimal to no geological activity presently.
Therefore, the mass of the planet or moon and the influence of external gravitational forces contribute to the differing levels of geological activity observed across the Solar System.