Scientists study Saturn’s moon. Its name is Mimas. It is 400 miles in diameter. The experts say that the moon is special. Something is not normal there.
There are two reasons for this. The moon’s core is either like a rugby ball, or it has an ocean inside.
Difficult words: diameter (line from side to side of a circle), core (the middle), either…or (there are only two options).
You can read the original story and watch the video in the Level 3 section.