Which idea is presented in both "Our Solar System: In Depth" and "Planets of Our Solar System"?
A.
Some planets take less time to orbit around the Sun than the others.
B.
The Kuiper Belt, which is beyond Neptune, includes the dwarf planet Pluto.
C.
Our solar system includes terrestrial planets as well as gas and ice giants.
In the past, people thought that Earth was the center of the universe.
OD.