What are moons?

• A. Large planets
• B. Rocky metallic objects that orbit the sun but are too small to be considered planets
• C. Comets with tails
• D. Smaller bodies that orbit planets

Answer: (D)

Moons are natural satellites—smaller bodies that orbit planets. They aren’t planets themselves and they don’t orbit the Sun. They can be rocky or icy and vary in size, with Earth's Moon as the classic example. Across the solar system, many planets have moons, showing that the defining idea is the object’s orbital relationship: it stays bound to a planet and travels around it rather than around the Sun. The other descriptions refer to objects that either orbit the Sun (like asteroids or comets) or are planets, which is why they don’t fit the concept of a moon.