F. Europa has a larger diameter than does Jupiter. G. Europa has a surface made of rocky material. H. Europa has a surface temperature of 20C. J. Europa is completely covered by a layer of ice.
F is not the best answer. Neither scientist discusses the diameter of Europa. In addition, the passage indicates that Europa is a moon of Jupiter, implying that Europa is smaller than Jupiter. Incorrect D is not the best answer. Scientist 1 says that the craters are smoothed by liquid water that oozes up into the crater from the subsurface and then quickly freezes.
Only a substantial amount of circulating liquid water can crack and rotate such large slabs of ice. The few meteorite craters that exist are shallow and have been smoothed by liquid water that oozed up into the crater from the subsurface and then quickly froze. Scientist 2 states that many of the features on Europa's surface resemble features created by flowing glaciers on Earth. So, neither scientist would agree that Europa's surface has remained unchanged for millions of years. Jupiter's magnetic field, sweeping past Europa, would interact with the salty, deep ocean and produce a second magnetic field around Europa. The spacecraft has found evidence of this second magnetic field. Scientist 2, no deep, liquid water ocean exists on Europa. The heat generated by gravitational tides is quickly lost to space because of Europa's small size, as shown by its very low surface temperature (160C).