Astronomy college course/Galilean moons of Jupiter/questions/Original version of this quiz

Galilean moons of Jupiter version A
{How does the density of a Galilean moon depend on its distance from Jupiter? } - all the moons have nearly the same density + the more dense moon is closer to Jupiter (always) - the density of the moons is unknown - the less dense moon is closer to Jupiter (always) - the most dense moon is neither the closest nor the most distant {How does the mass of a Galilean moon depend on its distance from the central body? } - the less massive moon is closer to Jupiter (always) - the mass of the moons is unknown + the most massive moon is neither the closest nor the most distant - the more massive moon is closer to Jupiter (always) - all the moons have nearly the same mass {Does Jupiter's moon Io have craters? } - no, the surface is too new - yes, from impacts + yes, from volcanoes - no, the surface is too old - yes, about half from impacts and the others from volcanoes {The mechanism that heats the cores of the Galilean moons is  } - radiation from the Sun and from Jupiter - tides from Jupiter - radioactive decay of heavy elements + tides from the other moons and Jupiter - radiation from the Sun {Immediately after publication of Newton's laws of physics (Principia), it was possible to "calculate" the mass of Jupiter. What important caveat applied to this calculation? } - The different moons yielded slightly different values for the mass of Jupiter. - The different moons yielded vastly different values for the mass of Jupiter. + Only the mass of Jupiter relative to that of the Sun could be determined. - tides from the other moons and Jupiter. - They needed to wait over a decade for Jupiter to make approximately one revolution around the Sun. {Ganymede, Europa, and Io have ratios in __________ that are 1:2:4. } - orbital period - Argon isotope abundance + Two other answers are correct (making this the only true answer). - density - rotational period {Which of Jupiter's moons has an anhydrous core? } - Europa - Ganymede - Two other answers are correct (making this the only true answer). + Io - Ganymede