According to paragraph 1, how do scientists know that Callisto is made up largely of ice? A. A sample of its interior was taken by the Galileo spacecraft in the late 1990s B. It has too low a density to contain much rocky metallic material C. With a noontime surface temperature of only about 140℃, the ice on it never melts D. All of the bodies in the Jovian system are icy, because they are so far from the Sun.