39. The inner planets Mercury, Venus, Earth, and Mars differ from the outer planets Jupiter, Saturn, Uranus, and Neptune in that the inner planets are made largely of
Answer: A
The inner planets are made largely of rocky material.
The inner planets, which include Mercury, Venus, Earth, and Mars, primarily consist of rocky materials, distinguishing them from their outer counterparts that are predominantly gas giants.
A) rocky material
This option is correct because the inner planets are characterized by their solid, rocky surfaces, which are composed of silicate rocks and metals. This composition allows them to maintain a solid form, unlike the outer planets.
B) gaseous material
This option is incorrect as it describes the outer planets, which are primarily composed of gases such as hydrogen and helium. The inner planets are not gaseous but rather have a solid structure.
C) hydrogen
This option is incorrect because while hydrogen is a significant component of the outer planets, it is not a primary material in the composition of the inner planets. Mercury, Venus, Earth, and Mars do not have substantial hydrogen content in their structures.
D) water vapor
This option is also incorrect as water vapor is not a major component of the inner planets' overall structure. While Earth contains water, it is not primarily composed of water vapor, and the other inner planets have very minimal water presence.
Conclusion
The correct answer is that the inner planets are made largely of rocky material, which is a defining characteristic that sets them apart from the gas giants of the outer solar system. All other options fail to accurately reflect the true composition of the inner planets, confirming the distinct geological and physical nature of these celestial bodies.