Final answer:
Callisto is an ancient, heavily cratered, and ice-covered moon of Jupiter that has remained geologically inactive, with its surface water ice never evaporating.
Step-by-step explanation:
Callisto's surface can be described as heavily cratered and ice-covered. This moon has remained geologically inactive for over 4 billion years, which is evident from its aged and cratered surface. Due to Callisto's low noontime surface temperature of 130 K, water ice is stable and never evaporates, maintaining a continuously icy landscape.
Unlike other large icy moons, Callisto has not fully differentiated into layers of different density materials, suggesting that it froze solid before the process of differentiation was complete. Its lack of a dense core was confirmed by its gravitational pull on the Galileo spacecraft. The large number of impact craters on its surface indicates its age and the absence of internal geological activity.