Which planet is the sixth from the Sun and is less dense than water?

Which planet is the sixth from the Sun and is less dense than water?

• A. Earth
• B. Venus
• C. Saturn
• D. Uranus

Answer: (C)

This question combines planet order by distance from the Sun with a density comparison. The sixth planet from the Sun is Saturn, a gas giant with a very low average density—about 0.69 g/cm³, which is less than water. That low density comes from its mostly light gases and huge size relative to mass. The other options don’t fit: Earth and Venus are closer to the Sun and have densities well above water, while Uranus is farther still (seventh) and also denser than water. So Saturn uniquely satisfies both conditions.

This question combines planet order by distance from the Sun with a density comparison. The sixth planet from the Sun is Saturn, a gas giant with a very low average density—about 0.69 g/cm³, which is less than water. That low density comes from its mostly light gases and huge size relative to mass. The other options don’t fit: Earth and Venus are closer to the Sun and have densities well above water, while Uranus is farther still (seventh) and also denser than water. So Saturn uniquely satisfies both conditions.