Question

in 2019, 20 previously unknown moons were confirmed to be orbiting saturn. three of the moons have prograde orbits (orbiting in the direction the planet spins), and the other 17 have retrograde orbits (orbiting in the opposite direction of the planet’s spin). all but one of the 20 moons are thought to be remnants of bodies that orbited saturn until they broke apart in collisions. although the one exceptional moon orbits in the same direction as the planet’s spin, its orbit is highly eccentric compared to the rest, which may suggest that it has a different origin than the other 19 moons. based on the text, which choice best describes the moon with the eccentric orbit? a) it doesn’t have a retrograde orbit, but it likely has the same origin as the moons with retrograde orbits. b) its orbit is so tilted with respect to the other moons’ orbits that it’s neither prograde nor retrograde. c) it has a prograde orbit that is likely the result of having collided with another body orbiting saturn. d) it has a prograde orbit and may not be a remnant of an earlier body that orbited saturn.

Explanation:

The text states that all but one of the 20 moons are remnants of bodies that broke apart in collisions. The exceptional moon orbits in the same direction as the planet's spin (prograde orbit) and has a highly eccentric orbit, suggesting a different origin than the other 19 moons. So it has a prograde orbit and may not be a remnant.

Answer:

D. It has a prograde orbit and may not be a remnant of an earlier body that orbited Saturn.