Final answer:
Terrestrial planets like Earth and Venus are geologically active with plate tectonics and volcanic activity, while gas giants lack a solid surface for such activity, though some of their moons show geologic dynamism due to tidal heating.
Step-by-step explanation:
The comparison of tectonic activity between terrestrial planets and the gas giants involves contrasting how internal processes have shaped their surfaces. Terrestrial planets, primarily Earth and Venus, exhibit the highest level of geological activity proportional to their mass, with Earth showcasing global plate tectonics and Venus having a similar volcanic landscape but with 'blob tectonics' rather than plate movements. Both Earth and Venus have molten interiors, are geologically active, and have surfaces that are being continually reshaped. Conversely, Mars has less activity, whereas the Moon and Mercury are largely geologically inactive.
Gas giant planets, being largely composed of gases and lacking a solid crust, do not have surface tectonics like terrestrial planets. However, some of their moons exhibit surprising levels of geological activity due to tidal heating, such as Io, Europa, and Enceladus. On terrestrial planets, geological features such as mountains can form from impacts, volcanism, or uplift, and their atmospheres may retain or lose materials from comet impacts, influencing their potential to support life.
In summary, terrestrial planets show a range of geological activities based on their size and proximity to other planetary bodies, with Earth and Venus being the most active, while the gas giants are different in their lack of solid surfaces but can have active moons due to tidal forces.