Final answer:
The Earth, Moon, and Mars have a different composition than Saturn and Jupiter due to the processes involved in planet formation in the inner solar system.
Step-by-step explanation:
The composition of the Earth, Moon, and Mars is different from that of Saturn and Jupiter due to the processes involved in planet formation in the inner solar system. Spectroscopic analysis shows that the terrestrial planets and the Moon are deficient in light gases and common elements like oxygen, carbon, and nitrogen. Instead, they are predominantly composed of heavy elements such as iron and silicon. This suggests that the lighter materials, which are more abundant on Saturn and Jupiter, might have escaped during the planet formation process in the inner solar system, leaving behind a residue of heavy elements.