Final answer:
Jovian planets, like Jupiter and Saturn, are primarily composed of hydrogen and helium, while terrestrial planets, like Earth and Mars, are composed primarily of rocks and metals. This difference in composition distinguishes jovian planets from other types of planets.
Step-by-step explanation:
The composition of jovian planets differs from other types of planets. Jovian planets, such as Jupiter and Saturn, are primarily composed of hydrogen and helium. On the other hand, terrestrial planets, like Earth and Mars, are composed primarily of rocks and metals, such as silicon and oxygen. This fundamental difference in composition is what sets jovian planets apart.