| A | B |
|---|
| The inner planets are called | terrestrial planets |
| The inner planets are called terrestrial planets because they resemble | Earth |
| Mars has features that resemble dry riverbeds showing evidence that it once had | liquid water |
| The current theory about the origin of the moon is that the moon resulted when a | large body struck Earth |
| The most useful unit for measuring distances within the solar system is the | astronomical unit |
| One way that gas giants differ from the terrestrial planers is their atmospheres are | massive |
| Active planets generally have fewer impacts than bodies like the moon because | activity removes their effect |
| Saturn is known for its spectacular | ring system |
